Producer system partitioning among leasing agent systems

ABSTRACT

Processes and systems are disclosed for partitioning a number of producer systems among a number of leasing agents. A leasing agent can identify a set of available producer systems within an environment and can partition the producer systems among each of the number of leasing agents. The leasing agent can then inform the other leasing agents of the producer systems assigned to each of the leasing agents. As the number of available producer systems change, the partitioning process can be repeated to rebalance the assignment of producer systems among the leasing agents.

RELATED APPLICATIONS

This application is related to the following applications: U.S.application Ser. No. 13/927,892, filed Jun. 26, 2013, and titled“MANAGING CLIENT ACCESS TO A PLURALITY OF COMPUTING SYSTEMS”; U.S.application Ser. No. 13/927,933, filed Jun. 26, 2013, and titled“PRODUCER SYSTEM SELECTION”; and U.S. application Ser. No. 13/927,995,filed Jun. 26, 2013, and titled “PRODUCER SYSTEM PARTITIONING AMONGLEASING AGENT SYSTEMS,” the disclosures of which are hereby incorporatedby reference in their entirety herein.

BACKGROUND

Often, computing resources and services are provided by a number ofcomputing systems. These computing resources and/or services may beconsumed by a number of additional computing systems. In many cases,several computing systems will provide access to the same resource orservice. Each of the computing systems that provide the resource orservice is typically limited in the number of requests that the systemcan process during a period of time.

To help provision services to the requesting computer systems, someenterprises utilize a centralized system that can track the usage ofeach system providing a service or resource. By using the centralizedsystem, the load on each of the provisioning systems can be balancedamong the several computing systems that provide the service orresource. One such centralized system is a hardware load balancer. Ahardware load balancer can help distribute requests among computingsystems that provide a service or resource thereby balancing the loadacross the provisioning systems of an enterprise.

BRIEF DESCRIPTION OF THE DRAWINGS

Throughout the drawings, reference numbers are re-used to indicatecorrespondence between referenced elements. The drawings are provided toillustrate embodiments of the inventions described herein and not tolimit the scope thereof.

FIG. 1A illustrates an embodiment of a network environment for providingconsumer systems with access to services hosted by producer systems.

FIG. 1B illustrates an embodiment of a network environment for providingconsumer systems with access to services hosted by producer systems andfor providing producer system health information to one or more leasingagents.

FIG. 2 illustrates an alternative view of an embodiment of a networkenvironment for providing consumer systems with access to serviceshosted by producer systems.

FIG. 3 illustrates an embodiment of a process for accessing a service ata producer system.

FIG. 4 illustrates an embodiment of a process for providing a consumersystem with a lease for a producer system.

FIG. 5 illustrates an embodiment of a producer system update process.

FIG. 6 illustrates an embodiment of a partitioning process forpartitioning a set of producer systems.

FIG. 7 illustrates an embodiment for a producer system registrationprocess from the perspective of a producer system.

FIG. 8 illustrates an embodiment for a producer system registrationprocess from a perspective of a leasing agent.

FIG. 9 illustrates an embodiment for a leasing agent repartitioningprocess.

FIG. 10 illustrates an embodiment for a hysteresis-based producerselection process.

FIG. 11 illustrates an embodiment of an overlay network environment forproviding consumer systems with access to services hosted by producersystems.

FIG. 12 illustrates an embodiment of a process for accessing a serviceat a producer virtual machine.

FIG. 13 illustrates an embodiment of a process for processing a requestto access a service at a producer virtual machine.

FIG. 14 illustrates an embodiment of a process for leasing access to aproducer virtual machine.

FIG. 15 illustrates an example of a state management table that can beused to facilitate communication in the overlay network environment.

DETAILED DESCRIPTION Introduction

Although hardware load balancers can be used to help prevent a computingsystem that provides access to a service or resource, which can betermed a producer system, from becoming overburdened with requests fromcomputing systems requesting access to the service or resource, whichcan be termed consumer systems, hardware load balancers may suffer froma number of drawbacks. For example, hardware load balancers provide asingle point of failure. In other words, if a hardware load balancermalfunctions, an associated enterprise system may become inaccessiblebecause service requests can no longer be forwarded to producer systems.Further, hardware load balancers can be expensive, opaque pieces ofhardware that make them unattractive solutions for load balancing anenterprise system.

One solution to the problems associated with hardware load balancers isto use decentralized load balancers. However, although decentralizedload balancers will address a number of the issues associated with usinga hardware load balancer, the decentralized load balancers tend to besuboptimal because they do not have a global view of the enterprisesystem and each load balancer is typically limited to servicing adefined subset of consumer and producer systems.

This disclosure describes embodiments of systems and processes thatutilize a set of leasing agents to allocate service requests from aplurality of consumer systems among a plurality of producer systems. Theleasing agents can monitor and allocate access, or leases, to a subsetof producer systems while, in most cases, being aware of the entireplurality of producer systems. Further, for each service request, asingle consumer system can interact with several leasing agents and, insome cases, multiple producer systems. The set of leasing agents can, incertain embodiments, serve as an amalgam load balancer in that theprocess of load balancing may be distributed among a set of distributedhardware-based systems with each leasing agent performing load balancingfor a subset of producer systems.

Advantageously, in certain embodiments, by partitioning producer systemsamong leasing agents while maintaining at least a subset of informationabout each producer system at each leasing agent, the advantages of bothhardware load balancers and decentralized load balancers can be achievedwithout the aforementioned drawbacks. Further, in certain embodiments,by not assigning consumer systems to specific leasing agents and/orproducer systems the load processed by each of the plurality of producersystems can be more balanced over time compared to a system thatseparates producer systems into isolated subsystems.

In some cases, systems and applications implemented on producer systemsand/or consumer systems are modified to function with the leasingagents. For example, as will be described further below, a consumersystem may be modified to lease access to producer systems and tomaintain status information of the producer systems.

In some embodiments, the systems and methods of the present disclosurecan be used with one or more overlay networks that are implemented ontop of a set of computing hosts that can host consumer virtual machinesand producer virtual machines. Advantageously, in certain embodiments,the systems and methods of the present disclosure can be implemented inthe networking infrastructure of the consumer hosts and producer hoststhereby enabling the leasing process to occur without involvement fromthe consumer and/or producer virtual machines.

When embodiments of the present disclosure are implemented in an overlaynetwork, instead of partitioning the producer systems among leasingagents, the producer virtual machines associated with each overlaynetwork may be separately partitioned among the leasing agents. Further,when leasing producer virtual machines to a consumer virtual machine,the leasing agents can select producer virtual machines assigned to thesame overlay network as the consumer virtual machine for which the leaseis being requested.

Network Environment Overview

FIG. 1A illustrates an embodiment of a network environment 100 forproviding consumer systems 104A-C with access to services hosted byproducer systems 106A-D. Generally, the network environment 100represents a single data center. However, in some cases, the systems ofthe network environment 100 may be distributed among a plurality of datacenters.

The network environment 100 can include a number of producer systems106A-D (which may be referred to herein singularly as “a producer system106” or in the plural as the producer systems 106″) and consumer systems104A-C (which may be referred to herein singularly as “a consumer system104” or in the plural as the consumer systems 104″). Although fourproducer systems 106 and three consumer systems 104 are illustrated, thenetwork environment 100 can include any number of producer systems 106and consumer systems 104. Further, although the network environment 100was previously described as representing one or more data centers, insome embodiments, at least some of the consumer systems 104 may beindependent of a data center. For example, in some embodiments, thenetwork environment 100 may be associated with a particular entity ororganization. In such embodiments, at least some of the consumer systems104 may represent user or customer computing systems that cancommunicate with the network environment 100, but which may be under thecontrol of an individual or separate entity than the rest of the systemsassociated with the network environment 100.

Generally, each of the producer systems 106 are capable of providing aservice and/or computer resource to a consumer system 104. In somecases, the producer systems 106 may each be capable of providing thesame services and/or resources to a consumer system 104. In other cases,at least some of the producer systems 106 may be capable of providingdifferent services and/or resources than other of the producer systems106. These services and/or resources that are provided by the producersystems 106 can include any type of service and/or computing resource.For example, the services and/or computer resources can include: datastorage access; external network access (e.g., access to the Internet);internal resource access (e.g., access to databases managed by the sameentity as the network environment 100); access to catalog services;access to directory services; access to an application; access toprocessing services (e.g., for distributed processing of a command orrequest); routing services (e.g., network routing services); etc. Tosimplify discussion, the rest of this disclosure will use the term“service” to refer to services, computer resources, or any otherresource that may be provided by or via a producer system 106, inaddition to the term “service” having its ordinary meaning herein.

The producer systems 106 can include any type of computing system. Forexample the producer systems 106 can include a client system, a server(e.g., an application server, a web server, etc.), a laptop, a desktop,a database system, a backup system, a directory system, a deduplicationsystem, a storage system, and the like. Similarly, the consumer systems104 can include any type of computing system. For example, the consumersystem 104 can include a client system, a server, a laptop, a desktop, atablet, a mobile phone, a gaming device, a television, etc. In someembodiments, a consumer system 104 can also serve as a producer systemand vice versa. For example, one consumer system 104 may access aproducer system 106 to obtain data (e.g., a producer system that servesas a database system or a storage system). The same consumer system 104may also serve as a producer system by, for example, providingapplication access to another consumer system 104. In some cases, theconsumer systems 104 and the producers systems 106 can be consideredclient and server systems respectively. However, as discussed above, theconsumer systems 104 and the producer systems 106 are not limited assuch.

Each time a consumer system 104 desires or requires access to a serviceprovided by a producer system 106, the consumer system 104 can accessone or more leasing agents 102A-102D (which may be referred to hereinsingularly as “a leasing agent 102” or in the plural as “the leasingagents 102”) to request access to a producer system 106 capable ofproviding the service. Generally, a consumer system 104 accesses somesubset of the leasing agents 102 to obtain the identity of a producersystem 106 to access to fulfill the service request. The subset ofleasing agents 102 can be randomly selected from the available leasingagents 102 and include several of the available leasing agents 102. Forinstance, the request to access a producer system 106 may be provided tothree of the four available leasing agents illustrated in FIG. 1A.However, in some cases, a consumer system 104 may be assigned tospecific leasing agents 102. Further, in some cases, a consumer system104 may provide a request to access a producer system 106 to a singleleasing agent 102 or to each existing leasing agent 102 in the networkenvironment 100.

FIG. 1A illustrates one example of communication between the leasingagents 102, the consumer system 104 and the producer systems 106. As canbe seen in FIG. 1A, each of the consumer systems 104 communicate withthree of the four available leasing agents 102. As indicated by thebroken arrows, this communication may include control informationincluding, for example, control information relating to requests toaccess a service provided by a producer system 106 and/or a request toaccess a producer system 106. Further, as indicated by the solid arrowsconnecting the consumer systems 104 to a subset of producer systems 106,the communication may include data relating to the producer systems 106servicing service requests by the consumers 104. In addition, theleasing agents 102 may communicate among themselves to provide, forexample, status information relating to the leasing agents 102 and/orthe producer systems 106. It should be noted that the illustratedintercommunication between the various systems of the networkenvironment 100 of FIG. 1A is but one example of the communicationbetween consumer systems 104, producer systems 106, and leasing agents102 and is not intended to be limiting. The communication between thevarious systems of the network environment 100 is described in furtherdetail with relation to the processes described herein with respect tothe FIG. 3-10.

FIG. 1B illustrates an embodiment of the network environment 100 forproviding consumer systems 104 with access to services hosted byproducer systems 106 and for providing producer system healthinformation to one or more leasing agents 102. As illustrated in FIG.1B, in some cases, data can be provided both from the producer systems106 to the consumer systems 104 and from the consumer systems 104 to theproducer systems 106. In other words, in some cases, data communicationcan be bidirectional.

Further, the producer systems 106 can provide health information to theleasing agents 102 thereby enabling the leasing agents 102 to trackwhich producer systems 106 are functioning and which producer systems106 have resources available to assign to a consumer system 104. In somecases, the producer systems 106 may provide the health information at ascheduled time. In other cases, the leasing agents 102 can request orping the producer systems 106 for health information. Often, eachproducer system 106 is assigned to a single leasing agent 102 asillustrated by producer systems 106A-106C. However, in some embodiments,producer systems 106 may be assigned to multiple leasing agents 102, asis the case with the producer system 106D.

Although FIGS. 1A and 1B illustrate different data and control channels,it is possible the network environment 100 to implement some or all ofthe data and control channels illustrated in FIGS. 1A and 1B. Thus,although FIG. 1B does not illustrate channels between the consumersystems 104 and the leasing agents 102, typically a control channelexists between the consumer systems 104 and the leasing agents 102 as isillustrated in FIG. 1A. Further, some or all of the channels may beunidirectional in which one system requests data, or controlinformation, and the other system provides data, or control information.Alternatively, or in addition, some or all of the channels may bebidirectional in which two systems in communication may both request andprovide data, or control information.

FIG. 2 illustrates an alternative view of an embodiment of the networkenvironment 100 for providing consumer systems 104 with access toservices hosted by producer systems 106. As illustrated in FIG. 2, eachof the systems of the network environment 100 can communicate with eachother via a network 202. The network 202 can include any type of wiredor wireless network and combinations of the same. For example, thenetwork 202 can include a Local Area Network (LAN), a Wide Area Network(WAN), a cellular network, an Ethernet-based network, a WiFi network, aWiLAN network, etc. Further, in some cases, the network 202 can includethe Internet.

As illustrated in FIG. 2, each of the systems described in Figure FIG.1A may include a number of subsystems, which may be implemented inhardware or software. For instance, the consumer systems 104 may includea lease requestor 240, a status module 242, a connection module 244, anda resource requestor 246. The lease requestor 240 may be configured torequest a lease of one or more producer systems 106 from one or moreleasing agents 102. In some cases, the lease requestor 240 mayspecifically request access to a producer system 106. In other cases,the lease requestor 240 may request access to a service with or withoutexplicitly requesting access to a producer system 106.

Once the lease requestor 240 has obtained the identity of one or moreproducer systems 106, the connection module 244 can attempt to establishcommunication with some or all of the producer systems 106 identified bythe leasing agents 102. After a connection has been established with aproducer system 106, the resource requestor 246 can request a resourceor service from the producer system 106 with which the consumer system104 has successfully established a connection.

The status module 242 can obtain status information relating to theproducer systems 106. This information can then be provided to theleasing agents 102 to facilitate the leasing agents 102 selectingproducer systems 106 in response to requests from consumer systems 104for access to a producer system 106. This information may be provided tocorresponding status modules 228 of the leasing agents 102. In somecases, the status module 242 obtains the status information based on thesuccess or lack of success in establishing a connection with theproducer systems 106. In other cases, the status information is obtainedby querying the producer systems 106 and/or corresponding status modules262 included as part of the producer systems 106. The status informationmay include any information regarding connecting with the producersystems 106 and/or the provisioning of service by the producer systems106. For example, the status information may include informationrelating to the success or lack thereof in establishing communicationbetween a consumer system 104 and a producer system 106. As anotherexample, the status information may include the number of consumersystems 104 accessing a producer system 106 during a given time period.Further examples, may include information relating to the responsivenessof a producer system 106, the capacity of a producer system 106, theresources available at a producer system, etc.

As illustrated in FIG. 2, the producer systems 106 may include aregistration module 260 and a status module 262. As previouslydescribed, the status module 262 may provide status information relatingto the producer system 106 to a consumer system 104 that requests statusinformation relating to the producer system 106. Further, in some cases,the status module 262 may provide status information to a leasing agent102 either on its own accord or in response to a request from theleasing agent 102.

The registration module 260 is configured to register the producersystem 106 with a leasing agent 102. In certain embodiments, theregistration module 260 may automatically register the producer system106 as part of an initialization routine when the producer system 106 isfirst activated. In other embodiments, the registration module 260 mayregister the producer system 106 in response to a command from a user orapplication. In some cases, the registration module 260 may reregister aproducer system 106 upon the producer system 106 determining that itsassigned leasing agent is no longer available.

As previously described, the leasing agents 102 may also include astatus module 228. The status 228 module can receive status informationfrom one or both of the consumer systems 104 and the producer systems106 regarding the status of the producer systems 106. In addition, thestatus module 228 may provide status information associated with aproducer system 106 to another leasing agent 102. Further, in somecases, the status module 228 may perform health checks of other leasingagents 102 by requesting status information from the other leasingagents 102. For example, the status module 228 may determine whether aleasing agent 102 is no longer available based on whether a health checkrequest is answered by the leasing agent 102. In some cases, the statusmodule 228 may perform health checks of the producer systems 106 byrequesting status information from the producer systems 106.

In addition to the status module 228, the leasing agents 102 can includea producer repository 220, a partitioning system 222, a leasing system224, and a registration module 226. The producer repository 220 caninclude any type of database, repository, or storage for storinginformation relating to the producer systems 106. For example, theproducer repository 220 can include status information associated withthe producer systems 106, the identity of the producer systems 106, andinformation relating to the assignments or partitions of the producersystems 106 among the leasing agents 102. In some embodiments, some orall of the information stored at the producer repository 220 may bestored at the agent repository 206 instead of or in addition to theproducer repository 220.

The partitioning system 222 can include any system that can partitionthe available producer systems 106 among the leasing agents 102 of thenetwork environment 100. Generally, the partitioning system 222partitions the available producer systems 106 into non-overlapping ornon-equivalent subsets and then assigns one subset to each leasing agent102. Thus, if there are four leasing agents 102, then the producersystems 106 may be divided into four subsets with one subset associatedwith each leasing agent 102. However, in some cases, the subsets may beoverlapping. In such cases, a producer system 106 may be assigned orassociated with multiple leasing agents 102. The process of partitioningthe producer systems 106 among the leasing agents 102 may occur when thenetwork environment 100 is first initialized. In addition, the processmay reoccur periodically. For example, the process of partitioning theproducer systems 106 may occur each time there is a change in the numberof available producer systems 106 or when there is a threshold change inthe available producer systems 106, whether through addition or deletionof available producer systems 106.

Each time a consumer system 104 requests access to a producer system 106from a leasing agent 102, the leasing system 224 can identify a producersystem 106 to lease to the consumer system 104 based on a number offactors including, for example, status information associated with theproducer system 106, the location of the producer system 106 (e.g., thegeographical location, the data center, the server rack, etc.), andwhether the producer system 106 has access to the resource the consumersystem 104 is seeking to access. Once the leasing system 224 hasidentified a producer system, the leasing system 224 can provide therequesting consumer system 104 with the identity of the producer system106. Further, in some cases, the leasing system 224 may provide theconsumer system 104 with a lease time that the consumer system 104 isauthorized to access the producer system 106. Alternatively, or inaddition, the leasing system 224 may provide the consumer system 104with a quantity of some other consumable resource or metric. Forexample, the consumable resource can be compute cycles, money, diskstorage, connection requests, etc.

The registration module 226 may serve as a counterpart to theregistration module 260 of the producer systems 106. Upon receiving arequest from a producer system 106 to register with a leasing agent 102,the registration module 260 of the leasing agent 102 may determinewhether the producer system 106 is assigned to the leasing agent 102. Ifso, the registration module 226 can register the producer system 106,which may include storing the availability status of the producer system106 as well as status information associated with the producer system106 at, for example, the producer repository 220. If on the other handthe registration module 226 determines that the producer system 106 isnot assigned to the leasing agent 102, the registration module 226 canidentify another leasing agent 102 that is assigned to the producersystem 106 and can inform the producer system 106 of the identity of theleasing agent 102 that is assigned to the producer system 106.

In certain embodiments, the network environment 100 may include an agentrepository 206 and/or a partitioning system 204. The agent repository206 may include information regarding the leasing agents 102 and/or theproducer systems 106 included in the network environment 100. Theinformation stored in the agent repository 206 may be used by one ormore of the leasing agents 102, the consumer systems 104, and theproducer systems 106. For instance, in some cases, the leasing agents102 may use the agent repository 206 to determine the number and/oridentity of the producer systems 106 of the network environment 100.Using this information, the leasing agents 102 can determine how topartition the producer systems 106. In some cases, the consumer systems104 may use the agent repository 206 to determine where a producersystem 106 is located after it is identified by a leasing agent 102 foraccess by the consumer system 104. As another example of using the agentrepository 206, in some cases, a producer system 106 may access theagent repository to determine the identity of a leasing agent 102 toaccess upon, for example, the producer system 106 first being activated.

In some embodiments, the partitioning system 204 may perform a processfor partitioning the producer systems 106 among the leasing agents 102.In such embodiments, the leasing agents 102 may not include their ownpartitioning systems 222.

In some embodiments, at least some of the modules included in theillustrated systems of FIG. 2 may be integrated with applications and/orresources provided by the systems. For example, the status module 262 ofthe producer systems 106 may be integrated with applications and/orresources provided by the producer systems 106. Similarly, the statusmodules 242 may be integrated with an application or service hosted bythe consumer systems 104.

Example Process for Accessing a Service at a Producer System

FIG. 3 illustrates an embodiment of a process 300 for accessing aservice at a producer system 106. The process 300 can be implemented byany system that can access a service or computer resource at a producersystem 106 by obtaining a lease or temporary authorization to access theproducer system 106 from a leasing agent 102. For example, the process300, in whole or in part, can be implemented by a consumer system 104, alease requestor 240, a connection module 244, a resource requestor 246,and a status module 242, to name a few. Although any number of systems,in whole or in part, can implement the process 300, to simplifydiscussion, portions of the process 300 will be described with referenceto particular systems.

The process 300 begins at block 302 where, for example, the leaserequestor 240 generates a lease request for access to a producer system106. In some cases, the lease request may include the identity of acomputer resource or service that a user of the consumer system 104 oran application on the consumer system 104 desires to access. In othercases, the lease request includes a request to access a producer system106 without specifying a service at the producer systems 106 to beaccessed by the consumer system 104.

At block 304, the lease requestor 240 provides the lease request to asubset of the leasing agents 102 included in the network environment100. In some cases, the lease requestor 240 may provide the leaserequest to some or all available leasing agents 102. The lease requestor240 may identify the available leasing agents 102 by accessing an agentrepository 206, which may include the identity of each leasing agent 102of the network environment 100. In other cases the consumer systems 104may each be configured with the identity of the leasing agents 102 uponinitialization or activation, or at any other time during operation ofthe consumer systems 104. For example, a user (e.g., an administrator)may provide the consumer systems 104 with the identity of the leasingagents 102. The identification of a leasing agent 102 may include a nameof the leasing agent 102, an address of the leasing agent 102 (e.g., anInternet Protocol (IP) address or other network address), and/or anyother information that can be used to identify the leasing agent 102within the network environment 100. In some embodiments, providing thelease request to a leasing agent 102 can include providing the leasingagent 102 with status information associated with one or more producersystems 106 with which the consumer system 104 has previouslyinteracted.

At block 306, the consumer system 104 receives an identification of aproducer system 106 from each of the subset of leasing agents 102 thatwere provided the lease request at the block 304. In some cases, theconsumer system 104 receives an identification of a producer system 106from some of the subset of leasing agents 102. For example, the consumersystem 104 may receive an identification of a producer system 106 fromone, two, or the entire subset of leasing agents 102. In cases where theconsumer system 104 does not receive the identity of any producer system106, the process 300 may end, the operations associated with the blocks302 and/or 304 may be repeated, and/or a user (e.g., an administratormay be alerted). In some cases, receiving the identification of aproducer system 106 includes receiving a length of time that theconsumer system 104 is authorized to access or lease access to theproducer system 106. Each leasing agent 102 from the subset of leasingagents 102 can provide the identity of a single producer system 106.However, in some cases, each of the leasing agents 102 from the subsetof leasing agents may provide the identity of multiple producer systems106. As with the identity of the leasing agent 102, the identity of theproducer system 106 can include any information that identifies theproducer system 106 to the consumer system 104 or that provides a methodto access the producer system 106. For example, the identity of theproducer system 106 can include a name, an address (e.g., an IPaddress), or an identifier that can be used to locate the producersystem 106 in a table or data structure stored, for example at the agentrepository 206.

In some cases, the block 306 may include receiving status informationfor the producer system 106 identified by each of the subset of leasingagents 102. This status information may be used to help the consumersystem 104 determine which producer system 106 to access. In some cases,the status information may be obtained by the leasing agents 102communicating with the producer system 106. Alternatively, or inaddition, the status information may be obtained from consumer systems104 who have previously communicated with the producer system 106. Thereceived status information may include an independent set or a subsetof the status information available to the leasing agents 102. In somecases, the received status information may or may not intersect with thestatus information available to the leasing agents 102.

The connection module 244, at block 308, attempts to initiate aconnection with each of the producer systems 106 identified at the block306. In some cases, the connection module 244 may attempt to initiate aconnection with a subset of the producer systems 106 identified at theblock 306. Attempting to initiate a connection can include any processfor attempting to open a communication channel with a producer system106. For example, attempting to initiate the connection can includesending a connection request packet to the producer system 106.Generally, the connection module 244 may attempt to establish aconnection with a producer system 106 as the consumer system 104receives the identity of the producer system 106. As the consumer system104 may rarely receive responses simultaneously from multiple leasingagents 102 because, for example, leasing agents 102 may be located atdifferent distances from the consumer system 104 or may have differentloads, the connection module 244 may rarely attempt to initiate aconnection with multiple producer systems 106 simultaneously. Instead,the attempts to initiate connection with the producer systems 106 may bestaggered, if even to a very small degree. However, in some embodiments,the connection module 244 may attempt to initiate connections withmultiple producer systems 106 simultaneously. For instance, in somecases, the consumer module 104 may wait until each of the subset ofleasing agents 102 responds, or in some situations, response may bereceived simultaneously from multiple leasing agents 102.

At block 310, the resource requestor 246 accesses or requests access toa service or a computer resource from the first producer system 106 withwhich the connection module 244 successfully establishes a connection.In some cases, successfully establishing a connection with the producersystem 106 can include receiving an acknowledge (“ack”) packet or thelike from the producer system 106. For similar reasons as describedabove with respect to the block 308, the connections with the producersystems 106 may be established in a staggered manner. However, in caseswhere the connection module 244 does successfully establish a connectionwith more than one producer system 106 simultaneously, or atsubstantially the same time, the resource requestor 246 can randomlyselect a producer system 106 from which to request access to a service.Alternatively, the resource requestor 246 can use a selection algorithmto determine which producer system 106 to request the service from. Theselection algorithm is not limited and can include, for example, roundrobin, least recently used (LRU), or any other type of selectionalgorithm. In some embodiments, the consumer system 104 may requestaccess to a service from some or all of the producer systems 106 withwhich a communication connection or communication channel has beenestablished. In some cases, the service may be of the same type. Inother cases, the consumer system 104 may request access to a differentservice from each producer system 106.

Further, in cases where a connection is successfully established withmore producer systems than the consumer system 104 requires at aparticular point in time, the consumer system 104 may relinquish thelease to the one or more additional producer systems 106. Alternatively,the consumer system 104 may maintain the leases to the additionalproducer systems 106 in a lease pool and may maintain the connections tothe additional producer systems 106. In such cases, if at some timeduring the lease period with the additional producer systems 106 theconsumer system 104 requires access to an additional service, theconsumer system 104 can utilize the services of one of the additionalproducer systems 106 whose lease was maintained in the lease pool.

At block 312, the status module 242 receives status metadata from thefirst connected producer system 106. In some cases, the status module242 may receive status metadata from each producer system 106 with whichthe connection module 244 successfully establishes a communicationchannel. Further, the status module 242 may obtain status metadata fromproducer system 106 that the connection module 244 has failed toestablish a communication channel with. For instance, the fact that theconnection module 244 has failed to establish the communication channelwith a particular producer system 106 may be included as status metadataassociated with the producer system 106. The status metadata is notlimited and can include information relating to establishing aconnection with the producer system 106, information relating tomaintaining the connection with the producer system 106, informationrelating to the responsiveness of the producer system 106, andinformation relating to the services available at the producer system106. For example the status metadata can include the amount of timeelapsed in connecting to the producer system 106, latency in theconnection to the producer system 106, available processing resources atthe producer system 106, the number of times a request must be resent tothe producer system 106 (e.g., due to a lost packet), and any other typeof data that can be associated with the status of the producer system106.

In some embodiments, the block 312 may be performed before the block310. In such cases, the status module 242 may receive status informationfrom each connected producer system 106. The consumer system 104 in suchcases can select the producer system 106 to access a service based onthe received status information.

At decision block 314, the consumer system 104 using, for example, theresource requestor 246 determines whether access to another service isdesired. This other service may be a different service, or it may be thesame type of service. For instance, in some cases, one service may befor accessing a network application and another service may be fordownload network resources (e.g., images or videos hosted by a networkpage, such as a webpage). Alternatively, both services may be used fordownloading network resources. For instance, a user may download twonetwork pages or resources from two network pages. If so, the connectionmodule 244 initiates connections with the identified producer systems106 at block 308. In some cases, the connection module 244 initiatesconnections with producer systems 106 identified in a lease poolassociated with the consumer systems 244. The lease pool can include theidentity of producer systems 106 that are currently leased to theconsumer system 104 for providing access to a resource. In some cases,the lease pool includes the producer systems 106 that are leased to theconsumer system 104, but which the consumer system 104 is not currentlyaccessing. If a lease pool does not include any leases, the consumersystem 104 may use, for example, the lease requestor 240 to perform theprocess 300 again. In some embodiments, the decision block 314 isoptional. For example, if no producer systems 106 are leased to theconsumer system 104, the process 300 may be repeated beginning with theblock 302.

In some embodiments, the process 300 can be used for renewing a previouslease to a producer system 106. In such cases, the lease requestgenerated at the block 302 can include the identity of the producersystem 106 that the consumer system 104 previously accessed. Further thelease request can include an indication that the request is a renewalrequest. The renewal lease request can then be provided to the leasingagent 102 that originally identified the producer system 106 to theconsumer system 104. Assuming that the leasing agent 102 determines thatthe producer system 106 is still available and/or has capacity forproviding service to the consumer system 104, the leasing agent 102 canindicate that the renewal request was approved and can provide a lengthof time for the renewal lease to the consumer system 104 as part of theblock 306. In cases where the consumer system 104 is maintaining a leasewith one or more additional producer systems 106 in a lease pool and thelease period lapses for the additional producer systems 106 without theconsumer system 104 utilizing services at the additional producersystems 106, the consumer system 104 can allow the leases to lapsewithout sending lease renewal requests to the leasing agents 102corresponding to the additional producer systems 106.

In some cases, the process of requesting a lease renewal may occur uponexpiration of an existing lease. In other cases, the consumer system 104using, for example, the resource requestor 246 may determine theprobability that an existing service request for accessing a service atone or more producer systems 106 will not be completed before a leasetime expires. If the probability satisfies a renewal threshold, theconsumer system 104 may request a renewal of the lease of the producersystem 106 at some point in time prior to expiration of an existinglease thereby reducing or preventing service outages due to leaseexpirations.

In certain embodiments, leasing access to a producer system 106 mayinclude providing payment to an organization or entity associated withone or more of the producer system 106 and/or the leasing agents 102.For example, the producer systems 106 may be made available as part of apay-for-access service. Alternatively, leasing access to a producersystem 106 may not require payment of any kind. In such embodiments,leasing refers to the temporary nature of the access to the producersystem 106 and not a financial lease.

Example Process for Providing a Consumer System with a Lease for aProducer System

FIG. 4 illustrates an embodiment of a process 400 for providing aconsumer system 104 with a lease for a producer system 106. The process400 can be implemented by any system that can provide a consumer system104 with the identity of a producer system 106. Further, the process 400can be implemented by any system that can lease access to a producersystem 106 to a consumer system 104. For example, the process 400, inwhole or in part, can be implemented by a leasing agent 102, a leasingsystem 224, and a status module 228, to name a few. Although any numberof systems, in whole or in part, can implement the process 400, tosimplify discussion, portions of the process 400 will be described withreference to particular systems.

The process 400 begins at block 402 where, for example, the leasingsystem 224 of a leasing agent 102 receives a request from a consumersystem 104 to lease access to a producer system 106. In some instances,the request may include the identity of a specific service or computingresource the consumer system 104 is seeking to access at the producersystem 106. As described in the previous section, in some cases, thelease request may include a request to renew an existing lease by theconsumer 104 of the producer system 106.

At block 404, the status module 228 may receive status metadata for oneor more producer system 106 from the consumer system 104. This receivedstatus metadata may include data associated with the consumer system's104 prior attempts to communicate with or access services from one ormore producer systems 106. For example, the received status metadata mayinclude latency information, data relating to the responsiveness ofrequests by the consumer system 104 to the producer system 106, or anyother information previously described with respect to the block 312.Further, the received status metadata may include data that the consumersystem 104 received from the producer system 106 and/or data statusmetadata that the consumer system 104 generated based on its interactionwith the producer system 106. In some embodiments, the block 404 may beoptional. For instance, if the request is the first request receivedfrom the consumer system 104, the consumer system 104 may not have anystatus metadata to provide to the leasing agent 102.

At block 406, the status module 228 updates producer system statusinformation based on the status metadata received at the block 404. Insome cases, updating the producer system status information may includeupdating an entry associated with a producer system 106 in the producerrepository 220. In some embodiments the block 406 may be optional.

Further, at block 408, the status module 228 provides at least some ofthe status metadata received at the block 404 to a second leasing agent.For instance, the leasing agent 102 performing the process 400 maydetermine that some of the status metadata is for a producer system 106assigned to a different leasing agent 102. In such a case, the leasingagent 102 may provide the status information to the leasing agent 102that is assigned to the producer system 106. In other cases, the leasingagent 102 may provide the status metadata to all leasing agents 102 thatthe leasing agent 102 is in communication with, which may be some or allof the leasing agents 102 of the network environment 100. Any type ofdata transmission, replication, and/or synchronization process may beimplemented within the network environment 100 to share the statusmetadata among the leasing agents 102. For instance, a flood fillalgorithm or Prim's algorithm may be used to share data among theleasing agents 102. Additional systems and methods that may be usedherein for sharing of data among the leasing agents 102 are describedin: U.S. application Ser. No. 12/980,133, filed Dec. 28, 2010, andtitled “DATA REPLICATION FRAMEWORK”; U.S. application Ser. No.12/980,153, filed Dec. 28, 2010, and titled “DATA REPLICATIONFRAMEWORK”; U.S. application Ser. No. 12/980,193, filed Dec. 28, 2010,and titled “DATA REPLICATION FRAMEWORK”; and U.S. application Ser. No.12/980,258, filed Dec. 28, 2010, and titled “DATA REPLICATIONFRAMEWORK.” Each of these aforementioned applications is herebyincorporated by reference in their entirety.

In some embodiments the block 408 is optional. For example, in someembodiments the consumer system 104 only provides status metadata to theleasing agent 102 for producer systems 106 assigned to the leasing agent102 that received the request at the block 402.

At block 410, the leasing system 224 selects a producer system based onthe producer status information associated with each producer system 106allocated or assigned to the leasing agent 102. In some cases theproducer status information is based on information provided by aconsumer system 104 (e.g. status metadata received at the block 404). Inother cases, the producer status information may be based on informationobtained by the leasing agent 102 communicating with the producer system106. For example, the leasing agent 102 may perform a health or statuscheck of each producer system 106 assigned to the leasing agent 102.These health checks can include pinging the producer system 106,requesting an update of resource availability from the producer system106, or any other process for obtaining information relating to thestatus of a producer system 106. Further, the producer statusinformation may be based on information received from other leasingagents 102.

In certain embodiments, selecting the producer system 106 may be based,at least in part, on weights associated with the different producersystems 106. These weights may be generated based on the producer statusinformation. For instance, producer status information that indicates aproducer system 106 has low latency and a low error rate whencommunicating with consumer systems 104 may lead to the producer system106 being weighted higher and consequently being more likely to beselected at the block 410. Conversely, a producer system 106 that oftendrops connections to consumer systems 104 may be weighted lower andconsequently less likely to be selected at the block 410.

In some cases, the selection of the producer system 106 may be based onany number of additional factors, such as the location of the producersystem 106 with relation to the consumer system 104. The locationinformation can include, for example, whether the producer system 106 islocated in the same data center or the same server rack as a consumersystem 104. Selecting the producer system 106 may be based, in somecases, on the service requested by the consumer system 104. In yet othercases, selection of the producer system 106 may be based in part on anamount of lease time requested by and/or previously allocated to theconsumer system 104. In some cases, the leasing system 224 may selectthe least loaded producer system 106. In other cases, the leasing system224 may select a producer system 106 from a set of producer systems 106with a load below a threshold. In some embodiments, the load of aselected producer system 106 is determined to have increased uponselection regardless of whether a consumer system 104 has established aconnection with the selected producer system 106. Advantageously, incertain embodiments, by recording an increased load for a selectedproducer system 106 regardless of established consumer connections tothe producer system, the probability of the same producer system 106being selected more than a threshold number of times within a timeperiod is reduced because although the actual load of the producersystem 106 may be low, the anticipated load of future connections to theconsumer system 104 is considered in selecting a producer system.

In some cases, selecting the producer system 106 at the block 410 mayinclude selecting the producer system 106 with the lowest load withrespect to one or more load metrics (e.g., connections, processorutilization, etc.). Alternatively, selecting the producer system 106 mayinclude selecting a producer system 106 that is among a set of producersystems 106 with a load below a threshold load. The selection of theproducer system 106 from among the set of producer system 106 with theload below the load threshold may be random, pseudo-random, or based ona selection algorithm (e.g., least recently used, median load, etc.).Advantageously, in some embodiments, by selecting a producer system 106from a set of producer system 106 instead of always selecting theproducer system 106 with the lowest load, the probability and/oroccurrence of load oscillations is reduced. Further, the occurrence ofload bubbles, or load hotspots, such as an occurrence of a subset ofsystems that are associated with a high load compared to the rest of thenetwork environment 100, travelling through the network environment 100is reduced.

At block 412, the leasing system 224 provides lease information to theconsumer system 104 for the producer system 106 selected at the block410. This lease information can include the identity of the producersystem 106 and, in some cases, an amount of lease time for which theconsumer system 104 is authorized to access the producer system 106. Aspreviously described, the identity of the producer system 106 caninclude any information that can facilitate locating and accessing theproducer system 106, such as a network address. In some embodiments,providing an identity of the producer system 106 can include providing acertificate or public key to facilitate communicating with the producersystem 106.

As previously indicated, in some cases the process 400 can be used forlease renewal requests. In such cases, the block 410 can includedetermining whether the producer system 106 for which the consumersystem 104 has requested a lease renewal is still available for lease.Determining whether the producer system 106 is still available for leasecan include determining whether the producer system 106 has resourcecapacity to continue servicing the consumer system 104. Further,determining whether the producer system 106 is still available for leasecan include determining whether one or more metrics of the producerstatus information associated with the producer system 106 satisfies anavailability threshold. For example, the determination can includechecking whether an error rate associated with the producer system 106is below a threshold error rate. If the producer system 106 is availablefor lease renewal, the leasing agent 102 can send the consumer system104 an updated lease for the producer system 106. If the leasing agent102 determines that the producer system 106 is not available for leaserenewal, the leasing agent 102 can report as such and/or provide leaseinformation for an alternative producer system 106.

Example Producer System Update Process

FIG. 5 illustrates an embodiment of a producer system update process500. The process 500 can be implemented by any system that can updatethe availability of producer systems 106 and that can repartition theproducer systems 106 among leasing agents 102. For example, the process500, in whole or in part, can be implemented by a leasing agent 102, apartitioning system 222, a partitioning system 204, a registrationmodule 226, and a status module 228, to name a few. Although any numberof systems, in whole or in part, can implement the process 500, tosimplify discussion, portions of the process 500 will be described withreference to particular systems.

The process 500 begins at decision block 502 where, for example, thestatus module 228 of a leasing agent 102 determines whether a statusupdate has been received from a producer system 106. The status updatemay be expected by the leasing agent 102 in response to a request sentby the leasing agent 102 to the producer system 106. Alternatively, thestatus module 228 may expect the status update due to an update scheduleassociated with each producer system 106. For example, in some caseseach producer system 106 may be configured to automatically ping orprovide a status update to an assigned leasing agent 102 on an hourly ordaily basis. If the status update is received, the process 500 returnsto decision block 502 to await the next status update. Further, thestatus module 228 may update producer status information associated withthe producer system 106 at the producer repository 220 and/or the agentrepository 206.

On the other hand, if the status update is not received at decisionblock 502 the status module 228 updates the status of the producersystem 106 to indicate the unavailability of the producer system 106 atblock 504. Updating the status of the producer system 106 can includestoring an indication in the producer repository 220 and/or the agentrepository 206 that the producer system 106 is not available to beleased to a consumer system 104. In some cases, even when a statusupdate is received at the decision block 502, the status module 228 mayupdate the status of the producer system at the block 504 to indicatethat the producer system 106 is not available. For example, if thereceived status information indicates that the producer system 106 ismalfunctioning, is servicing requests at a threshold rate, or isgenerating errors beyond a threshold error rate, then the status module228 may update the producer repository 220 and/or the agent repository206 to indicate that the producer system 106 is no longer available. Insome embodiments updating the producer status information of a producersystem 106 to indicate its loss of availability may include alerting anadministrator that the producer system 106 is no longer available.Updating producer system 106 status information is described in moredetail with respect to FIG. 10.

At decision block 506, the partitioning system 222 determines whether athreshold amount of producer systems 106 have become unavailable. Ifnot, the process 500 returns to the decision block 502 to await the nextstatus update. If the partitioning system 222 determines at the decisionblock 506 that a threshold amount of producer systems 106 have becomeunavailable the partitioning system 222 performs a producerrepartitioning process at the block 508. This producer systemrepartitioning process is described in further detail below with respectto FIG. 6. In some embodiments, one or both of the decision block 506and the block 508 are performed by the partitioning system 204.

Example Partitioning Process

FIG. 6 illustrates an embodiment of a partitioning process 600 forpartitioning a set of producer systems 106. The process 600 can beimplemented by any system that can track a change in the number ofavailable producer systems 106 and that can repartition the producersystems 106 among leasing agents 102. For example, the process 600, inwhole or in part, can be implemented by a leasing agent 102, apartitioning system 222, a partitioning system 204, a registrationmodule 226, and a status module 228, to name a few. Although any numberof systems, in whole or in part, can implement the process 600, tosimplify discussion, portions of the process 600 will be described withreference to particular systems.

The process 600 begins at block 602 where, for example, the statusmodule 228 tracks the delta of available producer systems 106. In somecases, the status module 228 tracks the absolute change in the number ofavailable producer systems 106. Alternatively, or in addition, thestatus module 228 tracks a rate of change in the number of availableproducer systems 106. The delta or change in available producer systems106 can be based on the addition of new producer systems 106 or the lossin availability of producer systems 106. In some embodiments, theprocess 500 may be used to identify the loss in availability of aproducer system 106. Further, the determination of available producersystems 106 may be based on user updates indicating the loss or additionof a producer system 106. Moreover, the addition of producer systems 106may be tracked based on registration attempts by producer systems 106.In some cases, the availability of a producer system 106 may bedetermined based on information provided by a consumer system 104.Further, the delta, or change, of available producers may be tracked interms of actual numbers or in terms of the percentage change in theavailability of producer systems 106.

In some embodiments, the producer systems 106 and/or delta of availableproducer systems 106 is tracked by each leasing agent 102.Alternatively, each leasing agent 102 tracks the producer systemsavailable that are assigned to the leasing agent 102. In addition, oralternatively, the count and/or delta of available producer systems 106is tracked by an independent system, such as the partitioning system204.

At decision block 604, the partitioning system 222 determines whetherthe delta of available producer systems 106 satisfies a threshold. Thisdelta can be an absolute value. In other words, the addition orsubtraction of producer systems 106 may be tracked. In certainembodiments, the addition and subtraction of producer systems 106 may betracked independently with a separate threshold associated with each.Thus, in some cases, one or both thresholds may be satisfied even if thetotal change of available producer systems is zero or does not satisfy acombined threshold. In some cases, the delta can represent a percentagechange and/or a rate of change. In such cases, the threshold may be apercentage threshold and/or a rate of change threshold.

If the delta does not satisfy the threshold, or if none of the deltassatisfy the corresponding thresholds, the status module 228 continues totrack the available producer systems 106, or the change in availableproducer system 106, at the block 602. On the other hand, if the deltasatisfies the threshold, or a delta satisfies a corresponding threshold,the partitioning system 222 notifies the other leasing agents 102 thatthe leasing agent 102 performing the process 600 is initiating apartitioning, or a repartitioning process, of the producer systems 106at the block 606. Advantageously, in certain embodiments, by notifyingthe other leasing agents 102 that the leasing agent 102 performing theprocess 600 is initiating a partitioning process, the process 600 avoidshaving multiple leasing agents 102 perform a partitioning process at thesame time, which may cause non-optimal results due, for example, to raceconditions in the counting and partitioning of the producer systems 106.In some embodiments, the block 606 may be optional. For example, in someembodiments a partitioning system 204 that is separate from the leasingagents 102 may perform the partitioning or repartitioning process.

At block 608, the partitioning system 222 obtains the identity of theavailable producer systems 106. The partitioning system 222 may obtainthe identity of the available producer systems 106 by accessing theproducer repository 220 and/or by accessing the agent repository 206. Insome cases, the partitioning system 222 may obtain the identity ofavailable producer systems 106 by contacting other leasing agents 102.

At block 610, the partitioning system 222 partitions the availableproducer systems 106 among the leasing agents 102. The partitioningsystem 222 can use any type of partitioning algorithm to partition theproducer systems 106. Generally, the partition of the producer systems106 among the leasing agents 102 generates non-overlapping ornon-equivalent sets of producer systems 106 that can be assigned to theleasing agents 102. However, in some cases, the partitioning may beoverlapping. Further, in some cases, the subsets may be unbalanced. Inother words, some leasing agents 102 may be assigned more producersystems 106 than other leasing agents 102. In cases where the subsetsare unbalanced, the number or percentage of producer systems 106assigned to a particular leasing agent 102 may be based, at least inpart, on the number of requests that the leasing agent 102 and/or theproducer systems 106 assigned to the leasing agent 102 can process. Forexample, a first leasing agent 102 may be assigned less producer systemsthan another leasing agent 102 if the first leasing agent is assignedproducer systems 106 that are capable of handling a greater number ofconsumer system 104 requests than other producer systems 106.

Further, in embodiments where some producer systems 106 can providedifferent services than other producer systems, the producer systems 106may be partitioned such that each leasing agent is assigned a producersystem that can offer a particular service. Alternatively, the producersystems 106 that can offer the particular service may be partitionedamong a select subset of leasing agents 102.

At block 612, the partitioning system 222 of the leasing agent 102 thatis performing the process 600 updates each of the other leasing agents102 in the network environment 100 with the identity of the producersystems 106 assigned to each of the leasing agents 102 upon completionof the block 610. In some embodiments, the block 612 can includeupdating the leasing agent 102 performing the process 600 with theidentity of producer systems 106 assigned to itself. Updating theleasing agent 102 with the identity of the producer systems 106 mayinclude updating a table or database at the producer repository 220. Insome cases, because the leasing agent 102 is performing the process 600,the block 612 is optional with respect to the leasing agent 102 and isperformed only with respect to the other leasing agents 102 included inthe network environment 100.

In some embodiments, the process 600 can be used to provide the initialpartitioning of producer systems 106 among the leasing agents 102. Forinstance, when the network environment 100 is first configured, thedelta of available producer systems 106 is likely to satisfy thethreshold of the decision block 604 as the available producer systems106 are activated. Alternatively, or in addition, a user may manuallyactivate a partitioning process as the network environment 100 is firstconfigured, or at any other time.

The process 600 has been described as partitioning the producer systems106 among the leasing agents 102. However, the process 600 is notlimited as such. In some cases, the process 600 may be used to partitionleases that can be provided to consumer systems 104 for accessing theproducer systems 106 among the leasing agents 102. For example, aleasing agent 102, or partitioning system 222, can identify a set ofavailable producer systems and determine a number of leases availablefor each producer system of the set of available producer systems. Theleasing agent 102 performing the process 600 may be the first leasingagent 102 to detect a threshold changed in available leases or may be aleasing agent 102 designated to perform lease partitioning. The leasingagent 102 may identify the number of leases available based on statusinformation received from each producer system 106 (e.g., duringregistration of the producer system 106). Alternatively, or in addition,the number of leases available may be determined based on the type ofproducer system 106 or on configuration information received from theproducer system 106 or a user (e.g., an administrator).

The leasing agent 102 may partition the number of leases available foreach producer system 106 among a plurality of leasing agent 102 byassigning each leasing agent 102 from the plurality of leasing agents102 a subset of leases from the number of leases available for eachproducer system 106. The number of leases may be partitioned equally orsubstantially equally among the leasing agents 102. In some cases, atleast some of the leasing agents 102 may be assigned one more or oneless lease due to the number of leases not being a multiple of thenumber of leasing agents 102. Further, in some cases, leases may not bedivided equally because, for example, configuration differences amongsome leasing agents 102 and/or some producer systems 106. In some cases,each leasing agent 102 is assigned a non-overlapping set of leases.Alternatively, at least some of the leases may be assigned to multipleleasing agents 102. In some embodiments, the plurality of leasing agents102 that are being partitioned the leases to the producer systems 106may be a subset of the leasing agents 102. For example, in some cases, asubset of leasing agents 102 may be assigned to a subset of producersystems 106.

After, or while, partitioning the number of leases, the leasing agent102 performing the process 600 may, for each leasing agent 102 of theplurality of leasing agents 102, provide the leasing agent 102 with thesubset of leases assigned to the leasing agent 102. Providing the leasesto each of the leasing agents 102 may include providing the number ofleases from each producer system 106 assigned to each leasing agent 102to each of the leasing agents 102. Alternatively, or in addition,providing the leases to each of the leasing agents 102 may includeproviding an identity of each assigned lease to the leasing agent 102.Further, providing the leases may include providing connectioninformation for communicating with the producer system 106 and/or forutilizing the lease of the producer system 106.

Advantageously, in some embodiments, partitioning the number of leasesavailable for each producer system 106 among the plurality of leasingagents 102 enables a balancing of the workload among the plurality ofleasing agents 102. In some cases, it is unnecessary for the leasingagent 102 performing the process 600 to provide itself the subset ofleases assigned to itself as it is performing the process 600. However,in some cases, the leasing agent 102 may provide itself with the leases.For example, in cases where the subsystem of leasing agent 102 thatperforms the partitioning (e.g., the partitioning system 222) and thesubsystem that receives and/or tracks the leases assigned to the leasingagent 102 differ, the leasing agent 102 that performs the process 600may provide itself with the identity of its assigned leases.

In some cases, the process 600 can be used to partition both theproducer systems 106 and leases associated with each of the producersystems 106 among the leasing agents 102.

Example Producer System Registration Process

FIG. 7 illustrates an embodiment for a producer system registrationprocess 700 from the perspective of a producer system 106. The process700 can be implemented by any system that can register a producer system106 with a leasing agent 102. For example, the process 700, in whole orin part, can be implemented by a producer system 106, a registrationmodule 260, and a status module 262, to name a few. Although any numberof systems, in whole or in part, can implement the process 700, tosimplify discussion, portions of the process 700 will be described withreference to particular systems.

The process 700 may occur each time a producer system 106 is firstactivated or initialized, or reactivated or reinitialized after, forexample, a period of inactivity or a system restart. In some cases theprocess 700 may occur or reoccur each time the producer system 106determines that its assigned leasing agent 102 is no longer available.The determination that the assigned leasing agent 102 is no longeravailable may be based, for example, on information received from auser, obtained from the agent repository 206, or if an ACK is notreceived from the assigned leasing agent 102 after the producer system106 provides a status update, such as the status update described withrespect to FIG. 5.

The process 700 begins at block 702 where, for example, the registrationmodule 260 accesses the identity of a set of leasing agents 102 from,for example, the agent repository 206. In some cases, the producersystem 106 may access the identity of the set of leasing agents 102 frominternal storage. For example, the producer system 106 may bepreconfigured with the identity of a set of leasing agents 102. In othercases, a user may specify a leasing agent 102 to access.

At block 704, the registration module 260 selects a leasing agent 102from the set of leasing agents 102 identified at the block 702. Theregistration module 260 may select the leasing agent 102 at random or byusing any other selection method, such as a round robin or leastrecently used method. In cases where the set of leasing agents 102 aresorted, the registration module 260 may select the first leasing agent102 in the sorted set. In certain embodiments, the block 704 may beoptional. For example, the block 704 is unnecessary in cases where auser specifies a leasing agent 102.

At block 706, the registration module 260 initiates, or attempts toinitiate, a connection with the leasing agent 102 selected at the block704. In some cases, attempting to initiate the connection with theleasing agent 102 includes an attempt to register with the leasing agent102.

At block 708, the registration module 260 receives a connection responsefrom the leasing agent 102. The registration module 260 determines atthe decision block 710 whether the connection response confirmsregistration of the producer system 106 or indicates the identity of asecond leasing agent 102. If the registration module 260 determines atthe decision block 710 that the connection response confirmsregistration of the producer system 106, the status module 262 providesstate information relating to the producer system 106 to the leasingagent 102 at the block 712. This state information can include anyinformation associated with the state or status of one or more metricsassociated with the producer system 106. For example, the stateinformation can include the availability of one or more computingresources (e.g., memory, processors, network bandwidth, applications,etc.), the number of consumer systems 104 whose service requests arebeing processed by the producer system, and any other informationassociated with the state of a producer system 106.

The process associated with the block 712 may occur upon theregistration module 260 determining that the connection responseconfirms registration of the producer systems 106. Alternatively, or inaddition, the process associated with the block 712 may occur at somelater time. Further, in some embodiments, the process associated withthe block 712 may occur on a continual basis, an intermittent basis, ormay occur in response to a request from the leasing agent 102 for anupdate of the producer system's 106 status. In other embodiments, theprocess associated with the block 712 may occur each time there is athreshold change in the state or status of the producer system 106. Forexample, the process associated with the block 712 may occur when theavailability of processing resources for the producer system 106 dropsto a threshold level.

If the registration module 260 determines at the decision block 710 thatthe connection response received at the block 708 includes theidentification of a second leasing agent, the registration module 260initiates a connection with the second leasing agent at the block 714.As will be described with respect to the process 800, the second leasingagent may include a leasing agent that a first leasing agent (e.g., theleasing agent identified at the block 704) determined to be associatedwith the producer system 106.

At block 716 the status module 262 provides state information to thesecond leasing agent. In certain embodiments the block 716 may includeone or more of the embodiments previously described with respect to theblock 712. In certain embodiments, the connection response received atthe block 708 indicates whether or not the registration by the producersystem 106 was successful without identifying any additional leasingagents. In such cases, if the registration of the producer system 106was not successful the producer system 106 may attempt to register orinitiate a connection with another leasing agent from the set of leasingagents identified at the block 702 and instead may repeat the blocks704, 706, 708, and 710 until a leasing agent 102 confirms registrationof the producer system 106.

In some embodiments, the second leasing agent identified at the decisionblock 710 is selected at random and/or is not necessarily associatedwith the producer system 106. In such cases, the block 714 can includeperforming one or more embodiments described above with respect to theblocks 708 and 710, but in relation to the second leasing agent. Inother words, a loop can be formed from block 714 to block 708. In suchcases, the decision block 710 may identify a third leasing agent if theconnection response from the second leasing agent identifies the thirdleasing agent instead of confirming registration of the producer system106. This loop may be repeated continuously until the producer system106 is successfully registered with a leasing agent 102. Alternatively,the loop may be performed a threshold number of times. If the thresholdis satisfied without the producer system 106 being successfullyregistered, an alert may be generated. For example, an administrator maybe informed (e.g., via an email or pop-up alert) that a producer system106 has failed to register with a leasing agent 102. In some cases, suchas an unexpected system failure, producer systems 106 may fail toregister or update their registrations with a set of leasing agents 102.In such cases, a consumer system 104 may access a cache of connectioninformation, or leases, to attempt to access a producer system 106.Advantageously, in certain embodiments, by using cache information thatmay be expired, downtime for resource access may in some cases bereduced or eliminated.

Example Producer System Registration Process

FIG. 8 illustrates an embodiment for a producer system registrationprocess 800 from a perspective of a leasing agent 102. The process 800can be implemented by any system that can register a producer system 106at a leasing agent 102. For example, the process 800, in whole or inpart, can be implemented by a leasing agent 102, a registration module226, and a status module 228, to name a few. Although any number ofsystems, in whole or in part, can implement the process 800, to simplifydiscussion, portions of the process 800 will be described with referenceto particular systems.

The process 800 begins at block 802 where, for example, the registrationmodule 226 receives a registration request from a producer system 106.In some embodiments, the registration request can include a certificateor encryption key associated with the producer system 106. Theregistration module 226 determines at the decision block 804 whether theproducer system 106 is assigned to the leasing agent 102. Determiningwhether the producer system 106 is assigned to the leasing agent 102 caninclude accessing the producer repository 220 and/or the agentrepository 206 to determine whether the producer system 106 is assignedto the leasing agent 102. Further, in some cases, determining whetherthe producer system 106 is assigned to the leasing agent 102 can includevarying the identity of the producer system 106 based, for example, on areceived identifier, certificate, or encryption key associated with theproducer system 106.

If the registration module 226 determines that the producer system 106is assigned to the leasing agent 102, the registration module 226confirms registration of the producer system 106 at block 806.Confirming registration of the producer system 106 can include informingthe producer system 106 that it is registered with the leasing agent102. Further, in some cases, the block 806 can include updating theproducer repository 220 and/or the agent repository 206 to indicate thatthe producer system 106 is available and has registered with the leasingagent 102. Moreover, in some embodiments, the block 806 can includeproviding the producer system 106 with access to a certificate and/orencryption key associated with the leasing agent 102 and/or assigned tothe producer system 106. This certificate and/or encryption key can beused for further communications between the producer system 106 and theleasing agent 102. Moreover, the certificate and/or encryption key canbe used for communications between the producer system 106 and theconsumer system 104, such as to verify the identity of the producersystem 106, or to secure data communicated between the two systems.

At block 808, the status module 228 receives state information from theproducer system 106. This state information can include some or all ofthe embodiments described above with respect to the state information ofthe block 712. The status module 228 at block 810 can update theproducer status information for the producer system 106 based, at leastin part, on the state information received at the block 808. Updatingthe producer status information can include updating an entry, or one ormore metrics at the producer repository 220 and/or the agent repository206 to reflect the status of the producer system 106.

If the registration module 226 determines at the decision block 804 thatthe producer system 106 is not assigned to the leasing agent 102, theregistration module 226, at block 812, identifies another leasing agentwith which the producer system 106 is assigned. At block 814 theregistration module 226 can provide to the producer system 106 theidentity of the leasing agent 102 to which the producer system 106 isassigned enabling the producer system 106 to contact the leasing agent102 identified at the block 812. In certain embodiments, block 812 andblock 814 can be optional. For example in some cases the registrationmodule 226 may inform the producer system 106 that it is not associatedwith the leasing agent 102 and therefore, that the registration requestreceived at the block 802 was unsuccessful without informing theproducer system 106 of an alternative leasing agent 102 to which theproducer system 106 is assigned.

Leasing Agent Repartitioning Process

FIG. 9 illustrates an embodiment for a leasing agent repartitioningprocess 900. The process 900 can be implemented by any system that canreassign a set of producer systems 106 assigned to a leasing agent 102.For example, the process 900, in whole or in part, can be implemented bya leasing agent 102, a partitioning system 222, and a partitioningsystem 204, to name a few. Although any number of systems, in whole orin part, can implement the process 900, to simplify discussion, portionsof the process 900 will be described with reference to particularsystems.

The process 900 begins at block 902 where, for example, a partitioningsystem 222 associated with a first leasing agent 102 receives anindication that another, or second, leasing agent 102 is no longeravailable. The indication that the second leasing agent 102 is no longeravailable may be determined based on, for example, a ping or a statuscheck. In other cases, a partitioning system 222 may determine that aleasing agent 102 is no longer available when a message is notacknowledged by the second leasing agent 102. In yet other embodiments,a user may specify that the second leasing agent is no longer available.In some instances, the process 900 may be performed by the partitioningsystem 204.

At block 904, the partitioning system 222 identifies producer systems106 assigned to the leasing agent 102 that is no longer available. Theproducer systems 106 may be identified by accessing the producerrepository 220 and/or the agent repository 206. At block 906, thepartitioning system 222 partitions the producer systems 106 identifiedat the block 904 among the remaining leasing agents 102. In some casesthe block 906 may include informing the remaining leasing agents 102that the partitioning process is occurring thereby preventing multipleleasing agents from simultaneously partitioning the identified producersystems 106 as previously described with respect to the block 610.

In some embodiments, the block 906 may include repartitioning all theavailable producer systems 106 and not just those assigned to theleasing agent 102 that is no longer available. In such embodiments, theblock 904 may include identifying all available producer systems 106. Aspreviously described, the partitioning of producer systems 106 may beoverlapping, non-overlapping, equivalent, non-equivalent, and/or may bebased on a producer type. Thus, in some embodiments, the block 906 mayinclude some or all of embodiments previously described with respect tothe block 610. Further, in some cases, the partitioning of the producersystems 106 that were assigned to the second leasing agent 102 may bebased, at least in part, on the type of the second leasing agent 102.For example, if the second leasing agent 102 was assigned exclusivelyproducer systems 106 that provide storage services, then the producersystems 106 that were assigned to the second leasing agent 102 may berepartitioned among a subset of leasing agents 102 that also areexclusively assigned to producer systems 106 that provide storageservices or resources.

At block 908, the partitioning system 222 updates the remaining leasingagents 102 with the identity of the producer systems 106 newly assignedto each of the leasing agents 102 that are still available.

In some embodiments, the process 900 may be used for the addition ofleasing agents 102 or the replacement of leasing agents 102. In suchcases, the block 904 may identify all available producer systems 106 forpartitioning at the block 906. In some cases, the available producersystems 106 may be the same producer systems 106 that were available atan earlier time period. In other cases, the set of producer systems 106may have changed due to loss of producer systems 106 or the addition ofproducer systems 106. In cases where there is a one-to-one substitutionof leasing agents 102, the new leasing agent may be assigned theproducer systems 106 of the leasing agent it is replacing. In suchcases, the block 906 may be optional and the block 908 may includeinforming the other leasing agents that the new leasing agent is nowassigned the producer systems 106 of the old leasing agent.

Example Hysteresis-Based Producer Selection Process

FIG. 10 illustrates an embodiment for a hysteresis-based producerselection process 1000. The process 1000 can be implemented by anysystem that can modify selection weights associated with the producersystems 106 so as to modify the selection of producer systems, such asthe selection of a producer system 106 as part of the block 410. Forexample, the process 1000, in whole or in part, can be implemented by aleasing agent 102, a status module 228, and a leasing system 224, toname a few. Although any number of systems, in whole or in part, canimplement the process 1000, to simplify discussion, portions of theprocess 1000 will be described with reference to particular systems.

The process 1000 begins at block 1002 where, for example, the statusmodule 228 receives status metadata associated with a producer system106 from a consumer system 104. This status metadata may includeinformation provided by the producer system 106 to the consumer system104 as well as information that the consumer system 104 has determinedbased on its interaction with the producer system 106. For example thestatus metadata may include information relating to the response time ofthe producer system 106, the amount of consumer systems 104 that theproducer system 106 is servicing at a given time, the amount of consumersystems 104 that the producer system 106 services on average over a timeperiod, etc. In some embodiments, the block 1002 can include some or allof the embodiments described above with respect to the block 404.

Further, in some cases, the status module 228 may receive statusmetadata associated with a set of producer systems 106 that the consumersystem 104 has communicated with since the last time the consumer system104 communicated with the leasing agent 102. The status metadata may bereceived as part of a renewal request from the consumer system 104 forrenewed access to a producer system 106. In other cases, the statusmetadata may be received as part of a new lease request from a consumersystem 104.

At block 1004, the status module 228 updates the producer statusinformation for one or more the producer systems 106 based oncorresponding status metadata received at the block 1002. Alternatively,or in addition, the status module 228 may determine that at least someof the received status metadata is for a producer system 106 associatedwith another leasing system 102 and thus, may provide the statusinformation to the leasing agent 102 assigned to the producer system106. In some cases, the processes associated with the blocks 1002 and1004 can serve as a type of “gossip algorithm” in that the consumersystem 104 is providing a leasing agent 102 with information about theconsumer system's 104 interactions with each of a number of producersystems 106 regardless of whether the leasing agent 102 is assigned toeach of the number of producer systems 106. In other words, the leasingagent 102 may obtain “gossip” about a producer system 106 that isassigned to another leasing agent 102. The leasing agent 102 can thenspread the “gossip” to the leasing agent 102 that is assigned to theproducer system 106. Advantageously, in certain embodiments, by usingthis “gossip algorithm” the leasing agents 102 can obtain statusmetadata in between scheduled status updates from the producer systems106. By obtaining status metadata from the consumer systems 104, as wellas the producer systems 106, the selection of producer systems 106 forlease can be further optimized compared to systems that do not use the“gossip algorithm.” Additional embodiments of systems and methods forobtaining “gossip,” or feedback information for selecting a computingsystem to provide a service is described in U.S. application Ser. No.12/544,517, filed Aug. 20, 2009, and titled “DECENTRALIZED REQUESTROUTING,” which is hereby incorporated by reference in its entirety. Insome embodiments, the block 1002 can include some or all of theembodiments described above with respect to the block 406 and/or theblock 408.

At decision block 1006, the status module 228 determines whether theupdated producer status information indicates a change in a load metricassociated with the producer system 106. The load metric can include anycharacteristic of a producer system 106 that has been selected formonitoring. This load metric can relate to the load that can beprocessed by the producer system 106. In some cases, the load metric caninclude any metric that relates to the health of a producer system. Somenon-limiting examples of load metrics can include, an error rate, amemory utilization rate, a count of connections with consumer systems,etc. If the updated producer status information does not indicate achange in the load metric at decision block 1006, the process 1000returns to the block 1002 to await new status metadata from a consumersystem 104.

In some embodiments decision block 1006 may alternatively oradditionally involve determining if there is a change in a valueassociated with one or more other metrics associated with the producersystem 106. For example the status module 228 may determine if theupdated producer status information indicates a change in response timeby a producer system 106 or a change in available resources by theproducer system 106. In some cases, the decision block 1006 may includecomparing an updated load metric measurement of the producer system 106to an average load metric measurement for producer systems 106 in thenetwork environment 100 or for producer systems assigned to the leasingagent 102.

If the updated producer status information indicates that there is achange in the load metric of the producer system 106, the status module228, at block 1008, modifies a selection weight associated with theproducer system 106 based, at least in part, on the changed load metricmeasurement. Modifying the selection weight can include increasing ordecreasing the selection weight based on whether the change in errorrate indicates an increased error rate or a decreased error rate. Insome embodiments, the producer system 106 is not associated with aselection weight. In such embodiments, if the change in load metric, orother tracked metric, detected at the decision block 1006 satisfies orexceeds a corresponding threshold, the status module 228 may identifythe producer system as malfunctioning or unavailable. In such cases, auser such as an administrator may be alerted if the load metric hasreached a threshold associated with identifying the producer system 106as no longer available or malfunctioning. Further, in some cases, theuser may be alerted if the load metric, or selection weight changes athreshold amount regardless of the availability of the producer system106.

In certain embodiments, the selection weight associated with theproducer systems 106 may be used to facilitate selecting an availableproducer system 106 to lease to a consumer system as part of the block410 associated with the process 400 previously described. The selectionweight and/or the availability status of the producer system 106 may bestored at the producer repository 220 and/or the agent repository 206.

Overlay Network Environment Overview

FIG. 11 illustrates an embodiment of an overlay network environment 1100for providing consumer systems with access to services hosted byproducer systems. The overlay network environment 1100 can include anytype of system that can provide one or more overlay networks, or virtualnetwork, to one or more organizations or entities. These overlaynetworks may be implemented on computing hardware that may form aphysical or non-virtual network. Some examples of overlay or virtualnetworks that may be used with the present disclosure are described inU.S. application Ser. No. 12/827,268 (now U.S. Pat. No. 8,296,459),which was filed on Jun. 30, 2010, the disclosure of which is herebyincorporated in its entirety by reference.

The overlay network environment 1100 includes leasing agents 102,consumer hosts 1104, and producer hosts 1106, each of which maycommunicate with one another via the network 202. Each of the leasingagents 102 may include some or all of the subsystems illustrated anddescribed with respect to FIG. 2. Thus, for example, the leasing agents102 may include a producer repository 220, a partitioning system 222, aleasing system 224, a registration module 226, and a status module 228.Although each of these subsystems of the leasing agents 102 can includethe same functionality as has previously been described with respect toFIG. 2, in some cases these subsystems may include modified oradditional capabilities. For example, in addition to, or instead of,receiving status information relating to consumer systems 104 andproducer systems 106, the status module 228 can receive statusinformation relating to one or more of the consumer hosts 1104, theproducer hosts 1106, the consumer virtual machines 1142, and theproducer virtual machines 1162. Similarly, the producer repository 220can include information relating to one or more of the consumer hosts1104, the producer hosts 1106, the consumer virtual machines 1142, andthe producer virtual machines 1162.

In some cases, the partitioning system 222 can be used to partitionproducer virtual machines 1162 among the leasing agents 102 of theoverlay network environment 1100. Further, producer virtual machines1162 associated with a particular overlay network can be partitionedindependently of producer virtual machines 1162 associated with otheroverlay networks. Thus, for example, the producer virtual machine B′ maybe partitioned to a leasing agent 102 independently of the producervirtual machine B″. In some cases, a subset of available leasing agents102 may be associated with a particular overlay network. In such cases,producer virtual machines 1162 and consumer virtual machines 1142associated with the particular overlay network may limit communicationsto the subset of available leasing agents 102.

Further, the leasing system 224 may select a producer virtual machine1162 to lease to a consumer virtual machine 1142 based on the overlaynetwork with which the producer virtual machine 1162 and the consumervirtual machine 1142 are associated. In some cases, selecting a producervirtual machine 1162 based on the overlay network may be in addition tothe factors previously described with respect to selecting a producersystem 106 to least to a consumer system 104. Moreover, the registrationmodule 226 can be used to register producer virtual machines 1162 withthe leasing agents 102.

Although only a single consumer host 1104 is illustrated in FIG. 11, theoverlay network environment can include a plurality of consumer hosts1104. Each of the consumer hosts 1104 may include a number of consumervirtual machines 1142. Some of the consumer virtual machines 1142 may beassociated with different overlay networks than other consumer virtualmachines 1142 hosted by the consumer host 1104. For example, theconsumer host 1104 includes two consumer virtual machines 1142 eachassociated with a different overlay network. The consumer virtualmachine A′ may be associated with a first overlay network, which mayalso include the producer virtual machine B′, and the consumer virtualmachine A″ may be associated with a second overlay network, which mayalso include the producer virtual machine B″.

In addition to the consumer virtual machines 1142, the consumer host1104 may include an overlay network proxy 1114, a lease requester 1130,a virtual machine mapping repository 1150, and a status module 1132. Theoverlay network proxy 1114 can include any system that can processservice requests from a consumer virtual machine 1142 and that canprovide a service request for processing to a producer host 1106 that ishosting a producer virtual machine 1162. In some embodiments, a servicerequest received from a consumer virtual machine 1142 may include avirtual address associated with a producer virtual machine 1162 or anon-existent system that the consumer virtual machine 1142 beliefs canprocess it service request. Upon receiving the service request with thevirtual address, the overlay network proxy 1114 can identify a producervirtual machine 1162 for processing the service request in the sameoverlay network as the consumer virtual machine 1142 that provided theservice request. The overlay network proxy 1114 can then replace thevirtual address with the address of the identified producer virtualmachine 1162. As will be described in more detail below, the producervirtual machine 1162 may be identified from a pool of leased producervirtual machines 1162 associated with the consumer virtual machine 1142that provided the service request. Further, the overlay network proxy1114 can wrap or encapsulate the service request with a header or anouter header that identifies a producer host 1106 that hosts theidentified producer virtual machine 1162 and that identifies theconsumer host 1104.

The virtual machine mapping repository 1150 can store the pools ofproducer virtual machines 1162 leased on behalf of the consumer virtualmachines 1142. Further, the virtual machine mapping repository 1150 canstore the identity of corresponding producer hosts 1106 that host theproducer virtual machines 1162. Storing the identity of producer virtualmachines 1162 and producer hosts 1106 can include storing addressinginformation for accessing the producer virtual machines 1162 and theproducer host 1106.

To obtain leases on behalf of consumer virtual machines 1142, theconsumer host 1104 can include a lease requester 1118 that can generatelease requests on behalf of a consumer virtual machine 1142 hosted by aconsumer host 1104. The lease requester 1118 can identify a specificoverlay network and/or a specific consumer virtual machine 1142 forwhich a lease of a producer virtual machine 1162 is being requested.

The status module 1132 can include some or all of the embodimentsdescribed above with respect to the status module 242. Further, thestatus module 1132 can provide status information for producer virtualmachines 1162 and/or producer hosts 1106 based on communications withthe producer virtual machines 1162 and the producer hosts 1106.

As with the consumer hosts 1104, the overlay network environment 1100can include any number of producer hosts 1106 each of which can includeone or more producer virtual machines 1162 associated with one or moreoverlay networks. Further, each of the producer hosts 1106 can includean overlay network proxy 1116, a virtual machine mapping repository1152, and a status module 1134.

Similar to the overlay network proxy 1114, the overlay network proxy1116 can include any system for processing service requests receivedfrom a consumer host 1104 and for processing responses to the receivedservice requests. Upon receiving a service request, the overlay networkproxy 1116 can determine the producer virtual machine 1162 to processthe service request based on information included in a header of theservice request. Further, in some cases, the service request mayidentify a specific overlay network, which may be used to facilitateidentifying the producer virtual machine 1162 to process the servicerequests.

The virtual machine mapping repository 1152 can store informationidentifying which producer virtual machines 1162 are associated withwhich overlay networks. Further, the virtual machine mapping repository1152 can store information to facilitate identifying which consumerhosts 1104 host particular consumer virtual machines 1142. Thisinformation can be used to determine a consumer host 1104 to provide aresponse to a service request.

As with the status module 1132, the status module 1134 can include oneor more of the embodiments previously described with respect to thestatus module 262. Further, the status module 1134 can provide statusinformation relating to the producer virtual machines 1162 to theleasing agents 102.

As indicated by the dashed lines of the consumer hosts 1104 and theproducer host 1106, the underlying systems that enable the processesdisclosed herein can be separated from the virtual machines that formthe one or more overlay networks of consumers (e.g., clients) andproducers (e.g., servers or service providers). In some cases, theunderlying systems (e.g., the overlay network proxies 1114 and 1116) canbe implemented as part of the networking infrastructure of the consumerhosts 1104 and the producer hosts 1106. Advantageously, in certainembodiments, by separating the underlying systems from the virtualmachines, the leasing structure can be implemented, maintained, andmodified without impacting the overlay networks.

In some embodiments, the consumer hosts 104 can host both consumervirtual machines 1142 and producer virtual machines 1162. Further, insome cases, the producer hosts 1106 can host both consumer virtualmachines 1142 and producer virtual machines 1162. Moreover, although theconsumer virtual machines 1142 and producer virtual machines 1162 havebeen described as virtual machines, they are not limited as such. Insome embodiments, the overlay networks may be assigned hardwareresources and/or software resources that are part of or are executed bythe consumer hosts 1104 and the producer hosts 1106. These resources maybe used in placed of the virtual machines to implement producer systemsand consumer systems as part of an overlay network.

In some cases, one or more of the processes previously described withrespect to the network environment 100 may be performed or modified tobe performed with respect to the overlay network environment 1100. Thus,for example, the process 900 may be performed to repartition leasingagents in the overlay network environment 1100. As a second example, theprocesses 700 and 800 can be performed to register a producer virtualmachine 1162 with a leasing agent 102 in the overlay network environment1100.

Example Process for Accessing a Service of a Producer Virtual Machine

FIG. 12 illustrates an embodiment of a process 1200 for accessing aservice at a producer virtual machine. The process 1200 can beimplemented by any system that can process a request from a consumervirtual machine to access a service provided by a producer virtualmachine. For example, the process 1200, in whole or in part, can beimplemented by a consumer host 1104, a leasing agent 102, an overlaynetwork proxy 1114, and a lease requestor 1118, to name a few. Althoughany number of systems, in whole or in part, can implement the process1200, to simplify discussion, portions of the process 1200 will bedescribed with reference to particular systems.

In some cases, the process 1200 may be used to enable a consumer virtualmachine to access a service provided by a producer system. Similarly, insome embodiments, the process 1200 may be used to enable a consumersystem to access a service provided by a producer virtual machine.However, to simplify discussion, the process 1200 will be described withrespect to a consumer virtual machine attempting to access a service ofa producer virtual machine.

The process 1200 begins at block 1202 where, for example, the overlaynetwork proxy 1114 of a consumer host 1104 (e.g., the consumer host A)receives from a consumer virtual machine 1142 (e.g., the consumervirtual machine A′) a request to access a service at a producer.Alternatively, or in addition, the request received at the block 1202may be a data packet to be provided to a producer. For example, the datapacket may be data to be used in conjunction with a service or forfacilitating use of a service at the producer for which the consumervirtual machine is already established access. In some embodiments, therequest may include a packet with a header indicating that the request,or the packet, is addressed to a virtual address X from an address Aassociated with the consumer virtual machine 1142. For instance, thereceived packet may be as follows: {A′, X, Data}, indicating that theData is being sent from A′ to X. The data field of the packet mayinclude a request and/or data to facilitate performing a request or anoperation at a producer virtual machine 1162. In certain embodiments,the consumer virtual machine 1142 may be unaware that the address X is avirtual address, but may instead believe that the address X refers to aphysical producer system. Moreover, as previously mentioned, in someembodiments an overlay network may comprise consumer systems other thanor in addition to consumer virtual machines. In such embodiments, theblock 1202 may include receiving a request to access the service at theproducer from a consumer system implemented on or hosted by a consumerhost 1104. Similarly, a producer host may include producer systems otherthan or in addition to producer virtual machines which may be configuredto provide services to consumer systems.

At decision block 1204, the overlay network proxy 1114 determines ifthere are any unused producer virtual machine leases associated with theconsumer virtual machine 1142. Determining if there are any unusedproducer virtual machine leases associated with the consumer virtualmachine 1142 may include accessing a virtual machine mapping repository1150 to determine if there is a lease pool associated with the consumervirtual machine 1142. Further, in some cases, the decision block 1204may include determining if the lease pool includes any unused leases forproducer virtual machines associated with the consumer virtual machine1142.

If the overlay network proxy 1114 determines at the decision block 1204that there are no unused producer virtual machine releases associatedwith the consumer virtual machine 1142, the lease requester 1130 obtainsa plurality of leases to access producer virtual machines at block 1206.An example of a process for obtaining one or more leases to access oneor more producer virtual machines is described in more detail withrespect to FIG. 14 below.

At block 1208, the overlay network proxy 1114 attempts to establishconnections with the leased producer virtual machines 1162 obtained atthe block 1206. In some cases, the block 1208 can include storing leaseinformation associated with each leased producer virtual machine forwhich the overlay network proxy 1114 successfully establishes aconnection.

After the overlay network proxy 1114 establishes connections with theleased producer virtual machines at the block 1208, or if the overlaynetwork proxy 1114 determines at the decision block 1204 that there areunused producer virtual machine leases associated with the consumervirtual machine 1142, the process 1200 proceeds to block 1210. At block1210, the overlay network proxy 1114 selects a leased producer virtualmachine 1162 from which to access the service requested by the consumervirtual machine 1142. The producer virtual machine 1162 may be selectedusing any type of selection algorithm, such as round-robin or leastrecently used. In other cases, the producer virtual machine 1162 may beselected based on the order that a connection was established with theproducer virtual machine 1162. In yet other cases, the producer virtualmachine 1162 may be selected at random and/or selected based on theservice request received that the block 1202. Alternatively, in somecases, the overlay network proxy 1114 may access the virtual machinemapping repository 1150 to facilitate selecting the producer virtualmachine 1142. For example, the overlay network proxy 1114 may access alease pool, which may be stored as a table identifying availableproducer virtual machines 1162, stored at the virtual machine mappingrepository 1150.

In some cases, the overlay network proxy 1114 may select a leasedproducer virtual machine 1162 that has a load below a threshold. In suchcases, the overlay network proxy 1114 may select at random from theproducer virtual machines 1162 that have a load below a threshold. Thisload may refer to any measurable metric that relates to the utilizationof the producer virtual machine 1162. For example, the load may refer toa processor load, a network connection load, a number of consumerconnections with the producer virtual machine 1162, a lowest latency ina connection, a measure of performance of the producer virtual machine1162, etc.

Further, in some cases, each lease may be associated with cost. Forexample, a consumer, or an entity associated with the consumer, may becharged for each second of use, for each megabyte of data communicatedor processed, or for each compute cycle of a producer virtual machine1162. In such cases, the overlay network proxy 1114 may select theleased producer virtual machine 1162 based on the cost of the availableleased producer virtual machines 1162.

At block 1212, the overlay network proxy 1114 replaces the address ofthe producer (e.g., the virtual address X) included in the requestheader (e.g., an inner header) with the address of the leased producervirtual machine 1162 that was selected at the block 1210. Thus, forexample, the packet received at the block 1202 may now be as follows:{A′, B′, Data}. In some embodiments, the block 1212 may be optional. Forexample, in some embodiments, each leased producer virtual machine 1162may be associated with a port. Thus, instead of replacing the virtualaddress X with an address of the leased producer virtual machine 1162,the packet may be communicated to the hosting producer via the portassociated with the leased producer virtual machine 1162. As a secondexample, the packet may be communicated to a producer host, and theproducer host may determine the leased producer virtual machine 1162 toreceive the packet based, for example, on the virtual address X.

At block 1214, the overlay network proxy 1114 identifies a producer host1106 associated with the leased producer virtual machine. The producerhost 1106 may be identified by accessing a state table stored at thevirtual machine mapping repository 1150.

The overlay network proxy 1114, at block 1216, encapsulates the requestwith an outer header identifying the producer host 1106 identified atthe block 1214 and the consumer host 1104 associated with the consumervirtual machine 1142. Thus, for example, the packet may now be asfollows: {A, B {A′, B′, Data}}, indicating that the packet is being sentfrom the consumer host A to the producer host B. Alternatively, in somecases, the identity of the producer host 1106 and the consumer host 1104may be included with or added to the request header of the requestreceived at the block 1202 and the packet may be as follows: {A, B, A′,B′, Data}, indicating that the packet is being sent from the consumerhost A to the producer host B. In such cases, after the processassociated with the block 1216 completes the request includes a singleheader instead of two headers comprising the inner header and the outerheader. In some embodiments, the block 1216 may include an identity ofthe overlay network associated with the consumer virtual machine 1142that provided the request at the block 1202 and the producer virtualmachine 1162 identified at the block 1210. Thus, for example, the packetmay indicate that the request is associated with the ′ or first overlaynetwork, as opposed to the ″ or second overlay network, as follows: {A,B, ′, A′, B′, Data}, indicating that the packet is being sent from theconsumer host A to the producer host B and that the service request isfrom a consumer virtual machine to a producer virtual machine includedin the ′ overlay network. Advantageously, in some embodiments, byincluding an identity of the overlay network with service requests andresponses to service requests, addresses may be reused among differentoverlay networks. However, in cases where each virtual machine and eachsystem is associated with a unique address, providing the identity ofthe overlay network may be optional.

In some embodiments, the overlay network proxy 1114 can determineaddress information for accessing producer virtual machines from a statemanagement table stored at the virtual machine mapping repository 1150.This state management table can include connection information foraccessing the leased producer virtual machine 1162 selected at the block1210. Further, the state management table can include a mapping ofvirtual addresses to producer virtual machine addresses. Additionally,the state management table can include a mapping of producer virtualmachines 1162 to their respective producer hosts. An example of such astate management table that maps virtual addresses to producer virtualmachines is illustrated in FIG. 15.

At block 1218, the overlay network proxy 1114 provides the request tothe producer host identified at the block 1214. This request may beprovided to the producer host 1106 via the network 202.

Example Process for Processing a Request to Access a Service at aProducer Virtual Machine

FIG. 13 illustrates an embodiment of a process 1300 for processing arequest to access a service at a producer virtual machine. The process1300 can be implemented by any system that can process a request toaccess a service at a producer virtual machine received from a consumerhost. For example, the process 1300, in whole or in part, can beimplemented by a producer host 1106, an overlay network proxy 1116, anda producer virtual machine 1162, to name a few. Although any number ofsystems, in whole or in part, can implement the process 1300, tosimplify discussion, portions of the process 1300 will be described withreference to particular systems.

In some cases, the process 1300 may be used to enable a producer virtualmachine to provide a service requested by a consumer system. Similarly,in some embodiments, the process 1300 may be used to enable a producersystem to provide a service requested by a consumer virtual machine.However, to simplify discussion, the process 1300 will be described withrespect to a producer virtual machine providing access to a servicerequested by a consumer virtual machine.

The process 1300 begins at block 1302 where, for example, the overlaynetwork proxy 1116 of a producer host 1106 (e.g., the producer host B)receives a request from a consumer host 1104. The request may beformatted, for example, as follows: {A, B, ′, A′, B′, Data}, indicatingthat the packet is being received from the consumer host A and isintended for the producer host B and that the service request is from aconsumer virtual machine to a producer virtual machine included in the ′overlay network. In many cases, the received request is a request toaccess a service hosted by a producer virtual machine 1162 posted by theproducer host 1106. However, in some cases, the received request mayinstead be a data packet configured to provide data to the producervirtual machine 1162 to facilitate performing a service for which accesshas already been established by a consumer virtual machine 1142 hostedby the consumer host 1104.

At block 1304, the overlay network proxy 1116 determines a producervirtual machine 1162 (e.g., the producer virtual machine B′) to receivethe request. In some embodiments, the block 1304 may includede-encapsulating an outer header from the request received at the block1302. In such cases, the packet may be as follows: {A′, B′, Data},indicating that the packet is being received from the consumer virtualmachine A′ and is intended for the producer virtual machine B′. In suchcases, the overlay network proxy 1116 may access an inner header toidentify the producer virtual machine 1162. Alternatively, or inaddition, the overlay network proxy 1116 may identify the producervirtual machine 1162 to receive the request by accessing the outerheader.

In some cases, the overlay network proxy 1116 provides the requestwithout an outer header to the producer virtual machine 1162 identifiedat block 1304. Thus, the packet may be as follows: {A′, B′, Data}.However, in other cases the request may be provided as received from theconsumer host 1104, including with the outer header if included with thereceived request. Thus, the packet may be as received at the block 1302(e.g., {A, B, ′, A′, B′, Data}).

At block 1308 the overlay network proxy 1116 receives a response fromthe producer virtual machine 1162 addressed to the consumer virtualmachine 1142 that caused the request received at the block 1302 to begenerated. In some embodiments, the response may be addressed to adifferent consumer virtual machine. For example, the request from theconsumer virtual machine may be a request to transfer files from theproducer virtual machine to another consumer virtual machine. Thispacket may be similar to the packet received at the block 1202 and maybe as follows: {B′, A′, Data}, indicating that the producer virtualmachine B′ is sending Data (e.g., a response to the service request) tothe consumer virtual machine A′. In block 1310, the overlay networkproxy 1116 identifies the consumer host 1104 associated with theconsumer virtual machine 1142. The consumer host 1104 may be identifiedby accessing a mapping table at the virtual machine mapping repository1152. This mapping table may map consumer virtual machines 1142 to theconsumer hosts 1104 that host the consumer virtual machines 1142.Typically, each consumer host 1104 may host a plurality of consumervirtual machines 1142. However, some cases one or more consumer hosts1104 may host a single consumer virtual machine 1142.

The overlay network proxy 1116, at block 1312, encapsulates the responsewith an outer header identifying the consumer host 1104 and the producerhost 1106 associated with the producer virtual machine 1162. Thus, thepacket may be as follows: {B, A {B′, A′, Data}}. As described withrespect to the block 1216, in some cases, the identity of the consumerhost 1104 and the producer host 1106 may be included with or added to anexisting header of the response received at the block 1308. Thus, thepacket may be as follows: {B, A, B′, A′, Data}. Similarly, as describedwith respect to the block 1216, the outer header, or the header of theresponse if only one header exists, may include an identity of theoverlay network associated with the producer virtual machine 1162 andthe consumer virtual machine 1142. Thus, the packet may be as follows:{B, A, ′, B′, A′, Data}.

The producer host 1106 provides the response to the consumer host 1104at block 1314. In some embodiments, the producer host 1106 may providethe response via a network 202.

In some embodiments, the consumer host 1104 may perform the process1300, or a similar process, to provide the response received at theblock 1308 to the corresponding consumer virtual machine 1142. Further,in some cases, the overlay network proxy 1114 of the consumer host 1104may identify a virtual address (e.g., the virtual address X) used tocreate an initial request provided by the consumer virtual machine 1142.Using this identified virtual address, the overlay network proxy 1114may replace an address in the received response identifying the producervirtual machine 1162 with the virtual address that was used to createthe initial request provided by the consumer virtual machine 1142. Thus,for example, before the packet is provided to the consumer virtualmachine A′, the packet may be reformulated as follows: {X, A′, Data},indicating that the response was received from system X instead of fromproducer virtual machine B′, which may actually have generated the Dataincluded in the packet.

Example Process for Leasing Access to a Producer Virtual Machine

FIG. 14 illustrates an embodiment of a process 1400 for leasing accessto a producer virtual machine. The process 1400 can be implemented byany system that can obtain a lease to access a producer virtual machine1162 (e.g., the producer virtual machine B′). For example, the process1400, in whole or in part, can be implemented by a consumer host 1104lease requestor 1130, a leasing agent 102, an overlay network proxy1114, and a leasing system 224, to name a few. Although any number ofsystems, in whole or in part, can implement the process 1400, tosimplify discussion, portions of the process 1400 will be described withreference to particular systems.

The process 1400 begins at block 1402 where, for example, the leaserequester 1130 generates a request to obtain a lease to a producervirtual machine 1162 for a consumer virtual machine 1142 associated withan overlay network. The process associated with the block 1402 may occurat initialization of the consumer virtual machine 1142. Alternatively,or in addition, the block 1402 may occur in response to a determinationthat there are no unused producer virtual machine leases associated withthe consumer virtual machine 1142 (e.g., as may be determined at thedecision block 1204 associated with the process 1200).

At block 1404, the lease requester 1130 provides the request to aplurality of leasing agents 102. In some embodiments, the plurality ofleasing agents 102 may comprise a subset of leasing agents 102 includedin the overlay network environment 1100. Further, in some cases, therequest may be provided to a single leasing agent 102.

At block 1406, the lease requester 1130 receives from each of theplurality of leasing agents 102 the identity of a producer virtualmachine 1162 associated with the same overlay network as the consumervirtual machine 1142 for which the request was generated at the block1402. Typically, each of the plurality of leasing agents 102 providesthe identity of a single producer virtual machine 1162. However, in somecases, one or more of the leasing agents 102 may provide the identity ofmultiple producer virtual machines 1162. Further, it is possible for aleasing agent 102 to provide the identity of zero producer virtualmachines 1162. For example, if each producer virtual machine 1162associated with a particular leasing agent 102 is utilized beyond athreshold utilization rate, the leasing agent 102 may not provide theidentity of a producer virtual machine 1162. In such a case, the leasingagent 102 may alert the user, such as administrator, that each producervirtual machine 1162 associated with the leasing agent 102 is utilizedabove a threshold utilization rate.

In some embodiments, in addition to receiving the identity of a producervirtual machine 1162, leasing information associated with leasing theproducer virtual machine 1162 may be received at the block 1406. Thisleasing information may include an address for accessing the producervirtual machine 1162, the identity and/or address of a producer host1106 that hosts the producer virtual machine 1162, and/or the identityof a consumable resource for an amount a consumable resource allocatedto the consumer virtual machine 1142 for the lease of the producervirtual machine 1162. This consumable resource may include any type ofresource for measuring a lease period of the producer virtual machine1162. For example, the consumable resource may include a period of time,a number of operations, an amount of data to be processed by and/orreceived from the producer virtual machine 1162, or any other metric formeasuring utilization of the producer virtual machine 1162 by theconsumer virtual machine 1142.

At block 1408, and overlay network proxy 1114 attempts to access, onbehalf of the consumer virtual machine 1142, each of the producervirtual machines 1162 identified at the block 1406. In some embodiments,the block 1408 can include attempting to establish connections with eachof the producer virtual machines 1162. In other embodiments, the block1408 can include attempting to communicate over established connectionswith the producer virtual machines 1162. At block 1410, the overlaynetwork proxy 1114 stores, in a lease pool, connection informationrelated to each established connection. This connection information mayinclude information for identifying a connection and how to use theconnection to access a service. For instance, the connection informationmay include any of the information received as part of the block 1406,such as the identity of the consumable resource for the identity of theproducer host 1106 that hosts the producer virtual machine 1162. In someembodiments, the lease pool and/or the connection information may bestored at the virtual machine mapping repository 1150.

Similar to the process 300, in some embodiments, the process 1400 may beused to renew a lease for a producer virtual machine 1162. In suchembodiments, the block 1402 may include generating a request to renew anexisting or previously existing lease for a producer virtual machine.The renewal request may include the identity of the existing producervirtual machine lease. Further, the block 1406 may include receiving anindication of whether the renewal request was granted and, in somecases, leasing information relating to an additional grant of aconsumable resource (e.g., lease time, or processor usage).

Example of a State Management Table

FIG. 15 illustrates one non-limiting example of a state management table1500 that can be used to facilitate communication in the overlay networkenvironment 1100. The state management table 1500 can include a numberof pieces of information that facilitate communication between aconsumer virtual machine 1142 and a producer virtual machine 1162. Forexample, the state management table 1500 may include a column for asource overlay address 1502, a source overlay port 1504, a virtualaddress 1506, and a destination overlay address 1508: As indicated bysome of the table headings (e.g., the source overlay address 1502) inthe state management table 1500, the address may be an Internet Protocol(IP) address. However, the addresses are not limited as such and maytake other forms or follow other protocols.

In the example of FIG. 15, the illustrated portions of the statemanagement table 1500 are associated with the consumer virtual machineA′. As shown in the virtual address 1506 column, the consumer virtualmachine A′ may use multiple virtual addresses, X and Y. Further, eachvirtual address may be associated with multiple destination overlayaddresses associated with multiple producer virtual machines. Forinstance, the virtual address Y may be associated with the producervirtual machine with the address K′ and with the producer virtualmachine with the address M′. As multiple destination addresses may bemapped to a virtual address, the overlay network proxy 1114 may alsoidentify a port, as indicated in the source overlay port 1504 column todirect the data packet to the right destination. Thus, to send theservice request to the producer virtual machine K′, the overlay networkproxy 1114 would substitute the virtual address Y with the address forK′ and use port P1. Similarly, to send the service request to theproducer virtual machine M′, the overlay network proxy 1114 wouldsubstitute the virtual address Y with the address for M′ and use portP2.

In many cases, an overlay network may be implemented using layer 3and/or layer 4 of the Open System Interconnection (OSI) model.Typically, with an overlay network implemented using layer 3 and/orlayer 4, the networking infrastructure is unaware of the applicationsthat are communicating across the network. This can make load balancingmore challenging because it is more difficult to anticipate a priori howmuch data will be transmitted between a consumer virtual machine and aproducer virtual machine.

One solution is to create a protocol aware load balancing system that isimplemented, at least in part, using layer 7 of the OSI model. In such asystem, the overlay network proxy 1114 can, in some embodiments, examinethe packets being transmitted by the consumer virtual machine 1142 todetermine the type of service the consumer virtual machine 1142 isattempting to access, or a protocol type associated with the servicerequest, and whether the service requests are for a single service, ormultiple services, of the same or of different types. Thus, for example,if the overlay network proxy 1114 determines that a consumer virtualmachine is requesting access to a website using HTTP requests, and eachHTTP request is for different webpages or different features of awebpage, the overlay network proxy 1114 can send the different requeststo different producer virtual machines 1162 for processing without theconsumer virtual machine 1142 being aware that the requests are beingprocessed by different systems. Thus, in some cases, a single connectionmay be demultiplexed over a set of connections. The overlay networkproxy 1114 may split a series of requests to multiple producer virtualmachines 1162 to increase efficiency or the rate that requests areprocessed. Further, if the overlay network proxy 1114 determines thatthe consumer virtual machine 1142 is creating a lot of load on aproducer virtual machine 1162, the overlay network proxy 1114 can swapthe producer virtual machine 1162 that is processing requests and/orsplit requests among multiple producer virtual machines 1162. Swappingthe producer virtual machine 1162 can be accomplished, in some cases, byassociating a request identifier with service requests. For example, asillustrated in the request identifier 1510 column of FIG. 15, packetswith a request identifier 11 can have the virtual address X swapped withthe address for the producer virtual machine B′. Likewise, packets witha request identifier 12 can have the virtual address X swapped with theaddress for the producer virtual machine D′.

Embodiments of the disclosure can be described in view of the followingclauses:

Clause 1: A method of leasing access to a producer system to obtainaccess to a service hosted by the producer system, the methodcomprising:

-   -   by a consumer system comprising one or more processors:        -   generating a lease request to access a service of one of a            plurality of producer systems;        -   providing the lease request to a plurality of leasing            agents;        -   receiving an identity of one or more of the producer systems            from individual leasing agents;        -   attempting to initiate a connection with at least some of            the producer systems identified by the plurality of leasing            agents; and        -   in response to successfully establishing a connection with a            first producer system from at least some of the producer            systems, accessing the service provided by the first            producer system.

Clause 2: The method of clause 1, wherein receiving the identity of oneor more of the producer systems from of the individual leasing agentscomprises receiving an identity of a different producer system from atleast two leasing agents of the plurality of leasing agents.

Clause 3: The method of clauses 1 to 2, wherein at least some of theindividual leasing agents of the plurality of leasing agents areassociated with a non-equivalent set of producer systems.

Clause 4: The method of clauses 1 to 3, wherein receiving the identityof one or more of the producer systems from individual leasing agentscomprises receiving a consumable resource for at least some of theidentified producer systems.

Clause 5: The method of clause 4, wherein the consumable resource cancomprise a lease time, a set of compute cycles, a monetary budgetassociated with use of the identified producer system, or disk storage,and wherein the lease time comprises a period of time that the consumersystem is authorized to access the service at the producer system.

Clause 6: The method of clause 5, wherein, in response to an amount ofconsumable resource remaining from the consumable resource for the firstproducer system satisfying a lease threshold, the method furthercomprises:

-   -   determining a probability that an existing service request for        accessing the service at the first producer will not be        completed before the consumable resource expires;    -   in response to determining that the probability satisfies a        renewal threshold, generating a renewal lease request to access        the service at the first producer system; and    -   providing the renewal lease request to the leasing agent from        the plurality of leasing agents that provided the identity of        the first producer system.

Clause 7: The method of clause 6, wherein, in response to providing therenewal lease request to the leasing agent, the method further comprisesreceiving a renewal amount of the consumable resource for the firstproducer system.

Clause 8: The method of clauses 6 to 7, wherein, in response toproviding the renewal lease request to the leasing agent, the methodfurther comprises receiving a new amount of consumable resource for anew producer system, the new producer system differing from the firstproducer system.

Clause 9: The method of clauses 1 to 8, wherein, in response tosuccessfully establishing the connection with the first producer systemfrom the at least some of the producer systems, the method furthercomprises obtaining metadata from the first producer system, wherein atleast some of the metadata comprises status information relating to thefirst producer system.

Clause 10: The method of clause 9, further comprising providing at leastsome of the metadata to the leasing agent from the plurality of leasingagents that provided the identity of the first producer system.

Clause 11: The method of clauses 9 to 10, further comprising providingat least some of the metadata to the plurality of leasing agents.

Clause 12: The method of clauses 1 to 11, wherein in response tosuccessfully establishing a connection with a second producer systemfrom the at least some of the producer systems, accessing a secondservice at the second producer system.

Clause 13: The method of clause 12, wherein the service and the secondservice are the same services.

Clause 14: The method of clauses 12 to 13, wherein data accessed usingthe service and data accessed using the second service differ.

Clause 15: A system for leasing access to a producer system to obtainaccess to a service hosted by the producer system, the systemcomprising:

-   -   a consumer system comprising one or more processors, the        consumer system further comprising a lease requestor configured        to:        -   generate a lease request to access a service of a producer            system;        -   provide the lease request to a plurality of leasing agents;            and        -   receive an identity of a producer system from at least some            of the plurality of leasing agents;    -   the consumer system further comprising a connection module        configured to attempt to initiate a connection with at least        some of the producer systems identified by the plurality of        leasing agents; and    -   the consumer system further comprising a resource requestor        configured to access the service at a first producer system of        at least some of the producer systems in response to the        connection module successfully establishing a connection with        the first producer system.

Clause 16: The system of clause 15, wherein the lease requestor isfurther configured to receive a lease time for at least some of theidentified producer systems, the lease time comprising a period of timethat the consumer system is authorized to access the service at theproducer system.

Clause 17: The system of clause 16, wherein the connection module isfurther configured to provide the lease time associated with the firstproducer system to the first producer system.

Clause 18: The system of clauses 16 to 17, wherein:

-   -   the resource requestor is further configured to determine a        probability that an existing service request for accessing the        service at the first producer will not be completed before the        lease time expires in response to an amount of time remaining        from the lease time for the first producer system satisfying a        lease threshold; and    -   the lease requestor is further configured to:        -   generate a renewal lease request to access the service at            the first producer system in response to determining that            the probability satisfies a renewal threshold; and        -   provide the renewal lease request to the leasing agent from            the plurality of leasing agents that provided the identity            of the first producer system.

Clause 19: The system of clauses 15 to 18, further comprising a statusmodule configured to:

-   -   obtain metadata from the first producer system, wherein at least        some of the metadata comprises status information relating to        the first producer system; and    -   provide at least some of the status information to the leasing        agent from the plurality of leasing agents that provided the        identity of the first producer system.

Clause 20: A system for leasing access to a producer system to provideaccess to a service hosted by the producer system, the systemcomprising:

-   -   a first leasing agent comprising a first leasing system, the        first leasing agent implemented in a computer system comprising        computer hardware, the first leasing system configured to:        -   receive a first request from a consumer system to lease            access to a service, the service provided by a number of            producer systems;        -   identify a first producer system from a first plurality of            producer systems based, at least in part, on producer status            information associated with individual producer systems of            the first plurality of producer systems, wherein the first            plurality of producer systems comprises a first subset of            the number of producer systems; and        -   in response to identifying the first producer system,            provide an identity of the first producer system to the            consumer system; and    -   a second leasing agent comprising a second leasing system        configured to:        -   receive a second request from the consumer system to lease            access to the service;        -   identify a second producer system from a second plurality of            producer systems based, at least in part, on producer status            information associated with the individual producer systems            of the second plurality of producer systems, wherein the            second plurality of producer systems comprises a second            subset of the number of producer systems, the second subset            of the number of producer systems non-identical to the first            subset of the number of producer systems; and        -   in response to identifying the second producer system,            provide an identity of the second producer system to the            consumer system thereby enabling the consumer system to            request access to the service from at least the first            producer system and the second producer system, whereby the            identification of producer systems is a distributed process            that is distributed between at least the first leasing agent            and the second leasing agent.

Clause 21: The system of clause 20, wherein the first leasing system isfurther configured to provide a first lease time to the consumer system,the first lease time comprising a period of time that the consumersystem is authorized to access the first producer system, and whereinthe second leasing system is further configured to provide a secondlease time to the consumer system, the second lease time comprising aperiod of time that the consumer system is authorized to access thesecond producer system.

Clause 22: The system of clauses 20 to 21, wherein:

-   -   the first leasing agent further comprises a first status module,        the first status module configured to:        -   receive first updated status information for the first            producer system; and        -   update the producer status information for the first            producer system based, at least in part, on the first            updated status information; and    -   the second leasing agent further comprises a second status        module, the second status module configured to:        -   receive second updated status information for the second            producer system; and        -   update the producer status information for the second            producer system based, at least in part, on the second            updated status information.

Clause 23: The system of clause 22, wherein the first updated statusinformation and the second updated status information are received fromthe consumer system.

Clause 24: The system of clause 22, wherein the first updated statusinformation is received from the first producer system and the secondupdated status information is received from the second producer system.

Clause 25: The system of clauses 20 to 24, wherein the first leasingagent is further configured to:

-   -   receive a first lease renewal request from the consumer system        to obtain additional lease time for the first producer system;    -   determining based, at least in part, on producer status        information for the first producer system whether to grant the        first lease renewal request; and    -   in response to determining to grant the first lease renewal        request, providing the consumer system with a first lease        renewal time for the first producer system.

Clause 26: The system of clause 25, wherein, in response to determiningnot to grant the first lease renewal request, the first leasing agent isfurther configured to:

-   -   identify a third producer system from the first plurality of        producer systems based, at least in part, on producer status        information associated with each producer system of the first        plurality of producer systems; and    -   in response to identifying the third producer system, provide an        identity of the third producer system to the consumer system.

Clause 27: A method for partitioning producer systems among a pluralityof leasing agent systems, the method comprising:

-   -   by a first leasing agent system comprising one or more        processors:        -   determining a first set of producer systems available at a            first time period;        -   identifying a second set of producer systems available at a            second time period, wherein the second time period occurs            prior to the first time period;        -   calculating a difference in number between the first set of            producer systems and the second set of producer systems;        -   determining whether the difference satisfies a threshold;            and        -   in response to determining that the difference satisfies the            threshold:            -   partitioning the first set of producer systems among a                plurality of leasing agent systems by assigning to                individual leasing agent systems a different subset of                the first set of producer systems; and            -   for individual leasing agent systems of the plurality of                leasing agent systems other than the first leasing agent                system, providing the individual leasing agent systems                with an identity of the subset of producer systems                assigned to the leasing agent system from the first set                of producer systems to enable different producer systems                from the first set of producer systems to provide                services to different consumer systems, whereby the                partitioning of the first set of producer systems among                the plurality of leasing agent systems enables a                balancing of an allocation of the services provided by                the first set of producer systems among the different                consumer systems.

Clause 28: The method of clause 27, further comprising notifying a setof leasing agent systems from the plurality of leasing agent systemsthat the first leasing agent system is partitioning the first set ofproducer systems causing the set of leasing agent systems to refrainfrom attempting to partition the first set of producer systems while thefirst leasing agent system is partitioning the first set of producersystems.

Clause 29: The method of clauses 27 to 28, wherein the second set ofavailable producer systems and the second time period comprise valuesthat ensure that the difference satisfies the threshold when the firstleasing agent system is activated after a period of non-activation.

Clause 30: The method of clauses 27 to 29, wherein the first set ofproducer systems comprises a total number of producer systems availableat the first time period and wherein the second set of producer systemscomprises the total number of producer systems available at the secondtime period.

Clause 31: The method of clauses 27 to 30, further comprising:

-   -   receiving an indication that at least one of the plurality of        leasing agent systems is not available at a third time period;    -   identifying a third set of producer systems available at the        third time period;    -   identifying a set of leasing agent systems available at the        third time period;    -   partitioning the third set of producer systems among the set of        leasing agent systems available at the third time period; and    -   for individual leasing agent systems of the set of leasing agent        systems available at the third time period, providing the        leasing agent system with the identity of a subset of producer        systems from the third set of producer systems, the subset of        producer systems determined based, at least in part, on said        partitioning of the second set of producer systems.

Clause 32: The method of clause 31, wherein the third set of producersystems and the first set of producer systems are the same systems.

Clause 33: The method of clauses 27 to 32, wherein partitioning thefirst set of producer systems available at the first time period amongthe plurality of leasing agent systems comprises dividing the first setof producer systems into non-overlapping subsets of producer systems.

Clause 34: The method of clauses 27 to 33, further comprising:

-   -   determining that a producer system from a first subset of        producer systems assigned to the first leasing agent system is        no longer available; and    -   updating a count of available producer systems to reflect that        the producer system is no longer available, wherein determining        the first set of producer systems available at the first time        period is based, at least in part, on the count of available        producer systems.

Clause 35: The method of clause 34, wherein determining that theproducer system is no longer available comprises receiving anotification from a consumer system that the producer system isunresponsive.

Clause 36: The method of clauses 34 to 35, wherein determining that theproducer system is no longer available comprises determining that theproducer system is unresponsive to a status request provided by thefirst leasing agent system.

Clause 37: The method of clauses 27 to 36, further comprising:

-   -   receiving a request from a producer system to register with the        first leasing agent system;    -   determining whether the producer system is included in the        subset of producer systems assigned to the first leasing agent        system; and    -   in response to determining that the producer system is included        in the subset of producer systems assigned to the first leasing        agent system, registering the producer system at the first        leasing agent system.

Clause 38: The method of clause 37, wherein, in response to determiningthat the producer system is not included in the subset of producersystems assigned to the first leasing agent system, the method furthercomprises:

-   -   identifying a second leasing agent system from the plurality of        leasing agent systems assigned to the producer system; and    -   providing the producer system with the identity of the second        leasing agent system.

Clause 39: The method of clauses 27 to 38, wherein a consumer systemfrom the different consumer systems accesses different producer systemsfrom the plurality of producer systems at different periods in time.

Clause 40: A system for partitioning producer systems among a pluralityof leasing agents, the system comprising:

-   -   a plurality of leasing agents including a first leasing agent,        wherein individual leasing agents from the plurality of leasing        agents comprise one or more processors, the first leasing agent        further comprising a partitioning system configured to determine        whether a difference between a set of available producer systems        at a first time period and the set of available producer systems        at a second time period satisfies a threshold; and    -   the partitioning system further configured to, in response to        determining that the difference satisfies the threshold:        -   partition the set of producer systems into multiple subsets            of producer systems based on a count of a number of leasing            agents included in the plurality of leasing agents to            attempt to cause access to the plurality of producer systems            by different user systems to be approximately evenly            distributed among the plurality of producer systems; and        -   provide, for individual leasing agents of the plurality of            leasing agents, an identity of producer systems included in            one of the subsets of producer systems to the leasing agent.

Clause 41: The system of clause 40, wherein a number of subsets ofproducer systems corresponds to the count of the number of leasingagents included in the plurality of leasing agents.

Clause 42: The system of clauses 40 to 41, the partitioning system isfurther configured to provide individual leasing agents with theidentity of producer systems included in a different subset of producersystems from the subsets of producer systems.

Clause 43: The system of clauses 40 to 42, wherein the partitioningsystem is further configured to alert one or more leasing agents of theplurality of leasing agents, not inclusive of the first leasing agent,that the partitioning system of the first leasing agent is partitioningthe set of producer systems.

Clause 44: The system of clauses 40 to 43, wherein, in response toreceiving an alert that a second leasing agent from the plurality ofleasing agents is partitioning the set of producer systems, thepartitioning system of the first leasing agent is further configured torefrain from partitioning the set of producer systems.

Clause 45: The system of clauses 40 to 44, wherein the first leasingagent further comprises a registration module configured to:

-   -   receive a request from a producer system to register with the        first leasing agent;    -   determine whether the producer system is included in a subset of        producer systems assigned to the first leasing agent;    -   in response to determining that the producer system is included        in the subset of producer systems assigned to the first leasing        agent, register the producer system at the first leasing agent;        and    -   in response to determining that the producer system is not        included in the subset of producer systems assigned to the first        leasing agent, identify a second leasing agent from the        plurality of leasing agents assigned to the producer system and        provide the producer system with the identity of the second        leasing agent.

Clause 46: A method of partitioning leases among a plurality of leasingagent systems, the method comprising:

-   -   by a first leasing agent system comprising one or more        processors:        -   identifying a set of available producer systems;        -   determining a number of leases available for individual            producer systems of the set of available producer systems;        -   partitioning the number of leases available for individual            producer systems among a plurality of leasing agent systems            by assigning individual leasing agent systems from the            plurality of leasing agent systems a subset of leases from            the number of leases available for individual producer            systems; and        -   for individual leasing agent systems of the plurality of            leasing agent systems, providing the leasing agent system            with the subset of leases assigned to the leasing agent            system, whereby the partitioning of the number of leases            available for individual producer systems among the            plurality of leasing agent systems enables a balancing of a            workload among the plurality of leasing agent systems.

Clause 47: The method of clause 46, wherein individual leasing agentsystems are assigned a non-overlapping subset of leases.

Clause 48: The method of clauses 46 to 47, wherein providing the leasingagent system with the subset of leases excludes providing the firstleasing agent system with the subset of leases assigned to the leasingagent system.

Clause 49: The method of clauses 46 to 48, wherein providing the leasingagent system with the subset of leases assigned to the leasing agentsystem comprises providing the leasing agent system with the number ofleases assigned to the leasing agent system for individual producersystems of the plurality of producer systems.

Clause 50: The method of clauses 46 to 49, wherein providing the leasingagent system with the subset of leases assigned to the leasing agentsystem comprises providing the leasing agent system with an identifierfor individual leases assigned to the leasing agent system.

Clause 51: The method of clauses 46 to 50, wherein partitioning thenumber of leases available for individual producer systems among theplurality of leasing agent systems comprises partitioning the number ofleases available for individual producer systems substantially equallyamong the plurality of leasing agent systems.

Clause 52: The method of clauses 46 to 51, wherein the plurality ofleasing agent systems comprises a subset of a set of leasing agentsystems.

Clause 53: The method of clause 52, wherein the plurality of leasingagent systems includes the first leasing agent system.

Clause 54: The method of clauses 46 to 53, wherein the set of availableproducer systems comprises a subset of available producer systems.

Clause 55: The method of clauses 46 to 54, wherein said partitioning thenumber of leases available for individual producer systems among theplurality of leasing agent systems occurs in response to a number oftotal leases available among the set of available producer systems at afirst time period changing a threshold amount compared to a second timeperiod.

Clause 56: A method for selecting a producer system from a plurality ofproducer systems to provide access to a service, the method comprising:

-   -   by a first leasing agent system comprising one or more        processors:        -   receiving status information for a plurality of producer            systems, wherein individual producer systems of the            plurality of producer systems are associated with a            selection weight, and wherein at least some of the status            information reflects a determination of the status of at            least one producer system by at least one consumer system;        -   modifying producer status information for the plurality of            producer systems based, at least in part, on the received            status information, the modified producer status information            comprising a set of metrics relating to a performance of the            plurality of producer systems with respect to interacting            with consumer systems;        -   modifying the selection weights associated with the            plurality of producer systems based, at least in part, on a            first metric from the set of metrics;        -   receiving a request from a consumer system to lease access            to one of the plurality of producer systems; and        -   in response to receiving the request to lease access to one            of the plurality of producer systems:            -   selecting a producer system from the plurality of                producer systems based, at least in part, on the                corresponding selection weight associated with                individual producer systems of the plurality of producer                systems to service the consumer system;            -   providing an identity of the selected producer system to                a consumer system that provided the request to lease                access to one of the plurality of producer systems; and            -   providing producer status information associated with                the selected producer system to the consumer system,                wherein at least some of the producer status information                is obtained from a second consumer system.

Clause 57: The method of clause 56, wherein the plurality of producersystems comprises a subset of producer systems.

Clause 58: The method of clauses 56 to 57, wherein modifying theselection weights associated with the plurality of producer systemsalters a probability that said selecting the producer system selects aspecific producer system.

Clause 59: The method of clauses 56 to 58, wherein the statusinformation is received from at least one consumer system.

Clause 60: The method of clause 59, wherein the at least one consumersystem includes the consumer system that provided the request to leaseaccess to one of the plurality of producer systems.

Clause 61: The method of clauses 56 to 60, wherein the statusinformation is received from the plurality of producer systems.

Clause 62: The method of clauses 56 to 60, wherein the statusinformation is received from a second leasing agent system.

Clause 63: The method of clauses 56 to 63, further comprising:

-   -   determining for a first producer system from the plurality of        producer systems whether a corresponding modified selection        weight satisfies a removal threshold; and    -   in response to the modified selection weight satisfying the        removal threshold, removing an identity of the first producer        system from a list of available producer systems, the list of        available producer systems comprising identities of available        producer systems corresponding to producer systems from the        plurality of producer systems that are available for selection.

Clause 64: The method of clause 63, wherein said selecting the producersystem from the plurality of producer systems comprises selecting theproducer system from the list of available producer systems.

Clause 65: The method of clauses 63 to 64, further comprising:

-   -   tracking a count of producer systems removed from the list of        available producer systems; and    -   in response to the count satisfying a reduction threshold,        repartitioning the available producer systems among a plurality        of leasing agent systems, the plurality of leasing agent systems        including the first leasing agent system.

Clause 66: The method of clause 63, wherein the removal threshold isbased on an average value of the first metric for the plurality ofproducer systems.

Clause 67: The method of clauses 56 to 66, wherein the producer statusinformation provided to the consumer system comprises an independent setof producer status information available to the first leasing agentsystem, and wherein the independent set of producer status informationenables the consumer system to select from a plurality of leasedproducer systems a less utilized producer system compared to the otherleased producer systems.

Clause 68: The method of clauses 56 to 67, wherein selecting theproducer system from the plurality of producer systems further comprisesselecting one of a first set of producer systems with a lower load thana second set of producer systems.

Clause 69: The method of clause 68, wherein the selected producer systemis not associated with a lowest load thereby reducing a frequency ofoccurrence of load oscillations.

Clause 70: A system for selecting a producer system from a plurality ofproducer systems to provide access to a service, the system comprising:

-   -   a first leasing agent of a plurality of leasing agents, the        first leasing agent comprising one or more processors configured        to implement a status module and a leasing system;    -   the status module configured to:        -   receive status information for a first producer system of a            plurality of producer systems, individual producer systems            from the plurality of producer systems associated with a            selection weight; and        -   modify the selection weight associated with the first            producer system based, at least in part, on the received            status information; and    -   the leasing system configured to:        -   receive a request to access one of the plurality of producer            systems; and        -   select a producer system from the plurality of producer            systems, including the first producer system, based, at            least in part, on the corresponding selection weight            associated with individual producer systems of the plurality            of producer systems to service the request.

Clause 71: The system of clause 70, wherein the status information isreceived at the first leasing agent by the leasing system and whereinthe leasing system is further configured to provide the statusinformation to the status module.

Clause 72: The system of clauses 70 to 71, wherein the status module isfurther configured to:

-   -   determine whether the first producer system is assigned to the        first leasing agent; and    -   in response to determining that the first producer is not        assigned to the first leasing agent, the status module is        further configured to:        -   identity a second leasing agent assigned to the first            producer; and        -   provide the received status information to the second            leasing agent.

Clause 73: The system of clauses 70 to 72, wherein the status module isfurther configured to:

-   -   determine whether the modified selection weight satisfies a        removal threshold; and    -   disassociate the first producer system from the plurality of        producer systems in response to the modified selection weight        satisfying the removal threshold.

Clause 74: The system of clause 73, wherein the first leasing agentfurther comprises a partitioning system configured to repartition theplurality of producer systems among the plurality of leasing agents inresponse to a number of producer systems disassociated from theplurality of producer systems satisfying a reduction threshold.

Clause 75: The system of clauses 70 to 74, wherein the leasing system isfurther configured to provide an identity of the producer system to aconsumer system that provided the request to access one of the pluralityof producer systems.

Clause 76: The system of clauses 70 to 75, wherein the selected producersystem comprises the first producer system.

Clause 77: Non-transitory physical computer storage comprisingcomputer-executable instructions that, when implemented in one or moreprocessors, direct a computing system to select a producer system from aplurality of producer systems to provide access to a service by atleast:

-   -   in response to receiving status information at a first leasing        agent for a first producer system of a plurality of producer        systems, determining whether the first producer is a member of a        first subset of producer systems, the first subset of producer        systems associated with the first leasing agent, wherein        individual producer systems from the plurality of producer        systems are associated with a selection weight, the plurality of        producer systems partitioned into a number of subsets of        producer systems;    -   in response to determining that the first producer system is a        member of the first subset of producer systems, modifying the        selection weight associated with the first producer system; and    -   in response to receiving a request to access a producer system,        selecting a second producer system from the first subset of        producer systems based, at least in part, on the selection        weights associated with the producer systems from the subset of        producer systems to service a provider of the request.

Clause 78: The non-transitory physical computer storage of clause 77,wherein the second producer system and the first producer system are thesame.

Clause 79: The non-transitory physical computer storage of clauses 77 to78, wherein, in response to determining that the first producer systemis not a member of the first subset of producer systems, the methodfurther comprises:

-   -   identifying a second subset of producer systems that includes        the first producer system;    -   identifying a second leasing agent associated with the second        subset of producer systems; and    -   providing the status information to the second leasing agent.

Clause 80: A method of accessing a service provided by a producervirtual machine in an overlay network, the method comprising:

-   -   by a consumer system host comprising one or more processors, the        consumer system host configured to host one or more consumer        virtual machines, wherein at least one of the consumer virtual        machines is associated with a first overlay network:        -   receiving a request to access a service at a producer system            from a consumer virtual machine, the consumer virtual            machine hosted by the consumer system host, wherein the            request includes an inner header, the inner header            comprising a consumer virtual machine address associated            with the consumer virtual machine and a target virtual            address;        -   accessing a lease pool associated with the consumer virtual            machine, the lease pool comprising a set of leased producer            virtual machines leased on behalf of the consumer virtual            machine;        -   selecting from the lease pool a leased producer virtual            machine from which to access the service;        -   replacing the target virtual address in the inner header            with a producer virtual machine address associated with the            leased producer virtual machine;        -   identifying a producer system host associated with the            leased producer virtual machine, the producer system host            configured to host one or more producer virtual machines,            wherein at least one of the producer virtual machines is            associated with the first overlay network;        -   encapsulating the request with an outer header comprising a            producer system host address associated with the producer            system host and a consumer system host address associated            with the consumer system host; and        -   providing the request to the producer system host via a            network, thereby enabling the producer system host to            process the request.

Clause 81: The method of clause 80, wherein selecting the leasedproducer virtual machine comprises:

-   -   determining whether the lease pool includes at least one        available leased producer virtual machine; and    -   in response to determining that the lease pool includes at least        one available leased producer virtual machine, selecting one of        the available leased producer virtual machines and removing the        selecting available leased producer virtual machine from the        lease pool.

Clause 82: The method of clause 81, wherein, in response to determiningthat the lease pool does not include an available leased producervirtual machine, the method further comprises:

-   -   obtaining, on behalf of the consumer virtual machine, leases for        a set of producer virtual machines included in the first overlay        network;    -   initiating connections with individual producer virtual machines        from the set of leased producer virtual machines; and    -   for individual successfully established connections, adding the        corresponding producer virtual machine to the lease pool,    -   wherein selecting the leased producer virtual machine further        comprises selecting one of the producer virtual machines added        to the lease pool and removing the selected producer virtual        machine from the lease pool.

Clause 83: The method of clause 82, wherein obtaining leases for the setof producer virtual machines comprises:

-   -   generating a request to obtain a lease to a producer virtual        machine included in the first overlay network for the consumer        virtual machine;    -   providing the request to obtain the lease to a producer virtual        machine to a set of leasing agents; and    -   for at least some of the leasing agents in the set of leasing        agents, receiving lease information for a producer virtual        machine thereby enabling a connection to be initiated with the        producer virtual machine.

Clause 84: The method of clause 83, wherein the set of leasing agentscomprises a subset of leasing agents in the network.

Clause 85: The method of clauses 80 to 84, further comprising:

-   -   receiving a response to a service request from the producer        system host;    -   de-encapsulating the service response by removing an outer        header of the response to obtain access to an inner header of        the response;    -   determining a recipient consumer virtual machine based on the        inner header of the response, the recipient consumer virtual        machine one of the consumer virtual machines hosted by the        consumer system host; and    -   providing the de-encapsulated service response to the recipient        consumer virtual machine.

Clause 86: The method of clause 85, wherein the recipient consumervirtual machine and the consumer virtual machine are the same.

Clause 87: The method of clauses 85 to 86, further comprising:

-   -   identifying, based on the inner header of the response, a source        virtual address associated with a source producer virtual        machine associated with the response; and    -   substituting an address included in the inner header associated        with the source producer virtual machine with the source virtual        address.

Clause 88: The method of clause 87, wherein the source producer virtualmachine corresponds to the selected leased producer virtual machine, thesource virtual address corresponds to the target virtual address, andthe recipient consumer virtual machine corresponds to the consumervirtual machine.

Clause 89: The method of clauses 80 to 88, wherein at least one of theconsumer virtual machines is associated with a second overlay network.

Clause 90: The method of clauses 80 to 89, wherein at least one of theproducer virtual machines is associated with a second overlay network.

Clause 91: The method of clauses 80 to 90, further comprising:

-   -   receiving a second request to access the service;    -   determining whether a load of the leased producer virtual        machine satisfies a load threshold; and    -   in response to determining that the load of the leased producer        virtual machine satisfies the load threshold:        -   selecting from the lease pool a second leased producer            virtual machine from which to access the service; and        -   providing the second request to a second producer system            host that hosts the second leased producer virtual machine.

Clause 92: The method of clause 91, wherein, in response to determiningthat the load of the leased producer virtual machine satisfies the loadthreshold, the method further comprises terminating a connection to theleased producer virtual machine.

Clause 93: A system for accessing a service provided by a producer in anoverlay network, the system comprising:

-   -   a consumer system host comprising one or more processors, the        consumer system host configured to host one or more consumers,        the consumer system host comprising:        -   a mapping repository configured to store a mapping of            producers to producer system hosts; and        -   an overlay network proxy configured to:            -   receive, from a consumer hosted by the consumer system                host, a request to access a service at a producer;            -   select a leased producer from which to access the                service, the leased producer leased on behalf of the                consumer;            -   access the mapping repository to identify a producer                system host associated with the leased producer, the                producer system host configured to host one or more                producers; and            -   send the request to the producer system host.

Clause 94: The system of clause 93, wherein:

-   -   the mapping repository is further configured to store a lease        pool associated with the consumer, the lease pool comprising a        set of leased producers leased on behalf of the consumer; and    -   the overlay network proxy is further configured to:        -   determine whether the lease pool includes at least one            available leased producer; and        -   select the leased producer from which to access the service            from the available leased producers in response to            determining that the lease pool includes at least one            available leased producer.

Clause 95: The system of clause 94, wherein, in response to determiningthat the lease pool does not include at least one available leasedproducer, the overlay network proxy is further configured to:

-   -   generate a request to obtain a lease to a producer for the        consumer;    -   provide the request to obtain the lease to a producer to a set        of leasing agents; and    -   for at least some of the leasing agents in the set of leasing        agents, receive lease information for a producer.

Clause 96: The system of clause 95, wherein the mapping repository isfurther configured to store the lease information in the lease poolassociated with the consumer.

Clause 97: The system of clauses 93 to 95, wherein the overlay networkproxy is further configured to:

-   -   receive a response to the request from the producer host system;    -   determine a recipient consumer based on an inner header of the        response, the recipient consumer comprising the consumer; and    -   provide the response to the consumer.

Clause 98: The system of clause 97, wherein the overlay network proxy isfurther configured to:

-   -   identify a source virtual address associated with the leased        producer; and    -   substitute an address included in the inner header associated        with the leased producer with the source virtual address prior        to providing the response to the consumer.

Clause 99: The system of clauses 93 to 97, wherein the overlay networkproxy is further configured to encapsulate the request with an outerheader comprising a producer system host address associated with theproducer system host and a consumer system host address associated withthe consumer system host.

Clause 100: Non-transitory physical computer storage comprisingcomputer-executable instructions that, when implemented in one or moreprocessors, direct a computing system to access a service provided by aproducer virtual machine in an overlay network by at least:

-   -   in response to receiving, from a consumer virtual machine hosted        by a consumer system host, a request to access a service at a        producer system, the request including a target virtual address,        selecting from a lease pool associated with the consumer virtual        machine a leased producer virtual machine from which to access        the service, the lease pool comprising connection information        for producer virtual machines leased on behalf of the consumer        virtual machine;    -   replacing the target virtual address in a header of the request        with a producer virtual machine address associated with the        leased producer virtual machine;    -   determining a producer system host associated with the leased        producer virtual machine; and    -   causing the request to be sent the producer system host to be        provided to the leased producer virtual machine thereby enabling        the lease producer virtual machine to process the request to        access the service.

Clause 101: The non-transitory physical computer storage of clause 100,wherein selecting from the lease pool associated with the consumervirtual machine the leased producer virtual machine comprises:

-   -   determining whether the lease pool includes connection        information for at least one leased producer virtual machine not        currently being used by the consumer virtual machine; and    -   in response to determining that the lease pool does not include        at least one leased producer virtual machine not currently being        used by the consumer virtual machine, the computer-executable        instructions further comprise directing the computing system to:        -   obtain, on behalf of the consumer virtual machine, leases            for a set of producer virtual machines included in an            overlay network;        -   initiating connections with individual producer virtual            machines from the set of leased producer virtual machines;            and        -   for successfully established connections, adding connection            information for the corresponding producer virtual machine            to the lease pool.

Clause 102: The non-transitory physical computer storage of clause 101,wherein selecting from the lease pool associated with the consumervirtual machine the leased producer virtual machine further comprisesselecting one of the producer virtual machines whose connectioninformation was added to the lease pool.

TERMINOLOGY

A number of computing systems have been described throughout thisdisclosure. The descriptions of these systems are not intended to limitthe teachings or applicability of this disclosure. For example, the usersystems described herein can generally include any computing device(s),such as desktops, laptops, video game platforms, television set-topboxes, televisions (e.g., internet TVs), computerized appliances, andwireless mobile devices (e.g. smart phones, PDAs, tablets, or the like),to name a few. Further, it is possible for the user systems describedherein to be different types of devices, to include differentapplications, or to otherwise be configured differently. In addition,the user systems described herein can include any type of operatingsystem (“OS”). For example, the mobile computing systems describedherein can implement an Android™ OS, a Windows® OS, a Mac® OS, a Linuxor Unix-based OS, or the like.

Further, the processing of the various components of the illustratedsystems can be distributed across multiple machines, networks, and othercomputing resources. In addition, two or more components of a system canbe combined into fewer components. For example, the various systemsillustrated as part of a leasing agent 102 can be distributed acrossmultiple computing systems, or combined into a single computing system.Further, various components of the illustrated systems can beimplemented in one or more virtual machines, rather than in dedicatedcomputer hardware systems. Likewise, the data repositories shown canrepresent physical and/or logical data storage, including, for example,storage area networks or other distributed storage systems. Moreover, insome embodiments the connections between the components shown representpossible paths of data flow, rather than actual connections betweenhardware. While some examples of possible connections are shown, any ofthe subset of the components shown can communicate with any other subsetof components in various implementations.

Depending on the embodiment, certain acts, events, or functions of anyof the algorithms, methods, or processes described herein can beperformed in a different sequence, can be added, merged, or left outaltogether (e.g., not all described acts or events are necessary for thepractice of the algorithms). Moreover, in certain embodiments, acts orevents can be performed concurrently, e.g., through multi-threadedprocessing, interrupt processing, or multiple processors or processorcores or on other parallel architectures, rather than sequentially.

Each of the various illustrated systems may be implemented as acomputing system that is programmed or configured to perform the variousfunctions described herein. The computing system may include multipledistinct computers or computing devices (e.g., physical servers,workstations, storage arrays, etc.) that communicate and interoperateover a network to perform the described functions. Each such computingdevice typically includes a processor (or multiple processors) thatexecutes program instructions or modules stored in a memory or othernon-transitory computer-readable storage medium. The various functionsdisclosed herein may be embodied in such program instructions, althoughsome or all of the disclosed functions may alternatively be implementedin application-specific circuitry (e.g., ASICs or FPGAs) of the computersystem. Where the computing system includes multiple computing devices,these devices may, but need not, be co-located. The results of thedisclosed methods and tasks may be persistently stored by transformingphysical storage devices, such as solid state memory chips and/ormagnetic disks, into a different state. Each process described may beimplemented by one or more computing devices, such as one or morephysical servers programmed with associated server code.

Conditional language used herein, such as, among others, “can,” “might,”“may,” “e.g.,” and the like, unless specifically stated otherwise, orotherwise understood within the context as used, is generally intendedto convey that certain embodiments include, while other embodiments donot include, certain features, elements and/or states. Thus, suchconditional language is not generally intended to imply that features,elements and/or states are in any way required for one or moreembodiments or that one or more embodiments necessarily include logicfor deciding, with or without author input or prompting, whether thesefeatures, elements and/or states are included or are to be performed inany particular embodiment. The terms “comprising,” “including,”“having,” and the like are synonymous and are used inclusively, in anopen-ended fashion, and do not exclude additional elements, features,acts, operations, and so forth. Also, the term “or” is used in itsinclusive sense (and not in its exclusive sense) so that when used, forexample, to connect a list of elements, the term “or” means one, some,or all of the elements in the list. In addition, the articles “a” and“an” are to be construed to mean “one or more” or “at least one” unlessspecified otherwise.

Conjunctive language such as the phrase “at least one of X, Y and Z,”unless specifically stated otherwise, is otherwise understood with thecontext as used in general to convey that an item, term, etc. may beeither X, Y or Z. Thus, such conjunctive language is not generallyintended to imply that certain embodiments require at least one of X, atleast one of Y and at least one of Z to each be present.

While the above detailed description has shown, described, and pointedout novel features as applied to various embodiments, it will beunderstood that various omissions, substitutions, and changes in theform and details of the devices or algorithms illustrated can be madewithout departing from the spirit of the disclosure. Thus, nothing inthe foregoing description is intended to imply that any particularfeature, characteristic, step, module, or block is necessary orindispensable. As will be recognized, the processes described herein canbe embodied within a form that does not provide all of the features andbenefits set forth herein, as some features can be used or practicedseparately from others. The scope of protection is defined by theappended claims rather than by the foregoing description. All changeswhich come within the meaning and range of equivalency of the claims areto be embraced within their scope.

What is claimed is:
 1. A method for partitioning producer systems amonga plurality of leasing agent systems, the method comprising: by a firstleasing agent system comprising one or more servers configured toperform load balancing across a plurality of producer systems, whereinindividual producer systems of the plurality of producer systemscomprise one or more servers configured to provide computing resources:monitoring a change in a number of available producer systems over time,the change resulting from at least one of an addition of one or more newproducer systems to the plurality of producer systems or a loss of oneor more existing available producer systems from the plurality ofproducer systems; determining whether a change in the number ofavailable producer systems from a first time period to a second timeperiod satisfies a threshold, wherein the first time period precedes thesecond time period; and in response to determining that the change inthe number of available producer systems from the first time period tothe second time period satisfies the threshold: partitioning theplurality of producer systems among the plurality of leasing agentsystems by assigning to individual leasing agent systems a differentsubset of the plurality of producer systems; and for individual leasingagent systems of the plurality of leasing agent systems other than thefirst leasing agent system, providing the individual leasing agentsystems with an identity of the subset of producer systems assigned tothe leasing agent system from the plurality of producer systems toenable different producer systems of the plurality of producer systemsto provide computing resources to different consumer systems, wherebythe partitioning of the plurality of producer systems among theplurality of leasing agent systems enables a balancing of an allocationof the computing resources provided by the plurality of producer systemsamong the different consumer systems.
 2. The method of claim 1, furthercomprising notifying a set of leasing agent systems from the pluralityof leasing agent systems that the first leasing agent system ispartitioning the plurality of producer systems causes the set of leasingagent systems to refrain from attempting to partition the plurality ofproducer systems while the first leasing agent system is partitioningthe plurality of producer systems.
 3. The method of claim 1, wherein thefirst time period and a number of producer systems available at thefirst time period comprise values that ensure that the change in thenumber of available producer systems from the first time period to thesecond time period satisfies the threshold when the first leasing agentsystem is activated after a period of non-activation.
 4. The method ofclaim 1, wherein a first set of producer systems is available at thefirst time period and a second set of producer systems is available atthe second time period, wherein the change in the number of availableproducer systems from the first time period to the second time periodequals a difference between a total number of producer systems in thefirst set and a total number of producer systems in the second set. 5.The method of claim 4, further comprising: receiving an indication thatat least one of the plurality of leasing agent systems is not availableat a third time period; identifying a third set of producer systemsavailable at the third time period; identifying a set of leasing agentsystems available at the third time period; partitioning the third setof producer systems available at the third time period among the set ofleasing agent systems available at the third time period; and forindividual leasing agent systems of the set of leasing agent systemsavailable at the third time period, providing the leasing agent systemwith an identity of a subset of producer systems from the third set ofproducer systems, the subset of producer systems determined based, atleast in part, on said partitioning of the third set of producersystems.
 6. The method of claim 5, wherein the third set of producersystems and the second set of producer systems are the same systems. 7.The method of claim 1, wherein partitioning a first set of producersystems available at the first time period among the plurality ofleasing agent systems comprises dividing the first set of producersystems into non-overlapping subsets of producer systems.
 8. The methodof claim 1, further comprising: determining that a producer system froma first subset of producer systems assigned to the first leasing agentsystem is no longer available; and updating a count of availableproducer systems to reflect that the producer system is no longeravailable.
 9. The method of claim 8, wherein determining that theproducer system is no longer available comprises receiving anotification from a consumer system that the producer system isunresponsive.
 10. The method of claim 8, wherein determining that theproducer system is no longer available comprises determining that theproducer system is unresponsive to a status request provided by thefirst leasing agent system.
 11. The method of claim 1, furthercomprising: receiving a request from a producer system to register withthe first leasing agent system; determining whether the producer systemis included in the subset of producer systems assigned to the firstleasing agent system; and in response to determining that the producersystem is included in the subset of producer systems assigned to thefirst leasing agent system, registering the producer system at the firstleasing agent system.
 12. The method of claim 11, wherein, in responseto determining that the producer system is not included in the subset ofproducer systems assigned to the first leasing agent system, the methodfurther comprises: identifying a second leasing agent system from theplurality of leasing agent systems assigned to the producer system; andproviding the producer system with an identity of the second leasingagent system.
 13. The method of claim 1, wherein a consumer system fromthe different consumer systems accesses different producer systems fromthe plurality of producer systems at different periods in time.
 14. Asystem for partitioning producer systems among a plurality of leasingagents, the system comprising: a plurality of leasing agents including afirst leasing agent, wherein individual leasing agents from theplurality of leasing agents comprise one or more servers configured toperform load balancing across a plurality of producer systems, whereinindividual producer systems of the plurality of producer systemscomprise one or more servers configured to provide services or computingresources, the first leasing agent further comprising a partitioningsystem configured to: monitor a change in a number of available producersystems, the change resulting from at least one of an addition of one ormore new producer systems to the plurality of producer systems or a lossof one or more existing available producer systems from the plurality ofproducer systems; and determine whether the change in the number ofavailable producer systems satisfies a threshold; and the partitioningsystem further configured to, in response to determining that the changein the number of available producer systems satisfies the threshold:partition the plurality of producer systems into multiple subsets ofproducer systems based on a count of a number of leasing agents includedin the plurality of leasing agents to attempt to cause access to theplurality of producer systems by different user systems to beapproximately evenly distributed among the plurality of producersystems; and provide, for individual leasing agents of the plurality ofleasing agents, an identity of producer systems included in one of thesubsets of producer systems to the leasing agent.
 15. The system ofclaim 14, wherein a number of subsets of producer systems corresponds tothe count of the number of leasing agents included in the plurality ofleasing agents.
 16. The system of claim 14, the partitioning system isfurther configured to provide individual leasing agents with theidentity of producer systems included in a different subset of producersystems from the subsets of producer systems.
 17. The system of claim14, wherein the partitioning system is further configured to alert oneor more leasing agents of the plurality of leasing agents, not inclusiveof the first leasing agent, that the partitioning system of the firstleasing agent is partitioning the plurality of producer systems.
 18. Thesystem of claim 14, wherein, in response to receiving an alert that asecond leasing agent from the plurality of leasing agents ispartitioning the plurality of producer systems, the partitioning systemof the first leasing agent is further configured to refrain frompartitioning the plurality of producer systems.
 19. The system of claim14, wherein the first leasing agent is further configured to: receive arequest from a producer system to register with the first leasing agent;determine whether the producer system is included in a subset ofproducer systems assigned to the first leasing agent; in response todetermining that the producer system is included in the subset ofproducer systems assigned to the first leasing agent, register theproducer system at the first leasing agent; and in response todetermining that the producer system is not included in the subset ofproducer systems assigned to the first leasing agent, identify a secondleasing agent from the plurality of leasing, agents assigned to theproducer system and provide the producer system with an identity of thesecond leasing agent.
 20. A method of partitioning leases among aplurality of leasing agent systems, the method comprising: by a firstleasing agent system comprising one or more servers configured toperform load balancing across a plurality of producer systems, whereinindividual producer systems of the plurality of producer systemscomprise one or more servers configured to provide services or computingresources: monitoring a change in a number of leases available for a setof available producer systems, the change resulting from at least one ofan addition of one or more new producer systems to the plurality ofproducer systems or a loss of one or more existing available producersystems from the plurality of producer systems; determining whether thechange in the number of leases available for the set of availableproducer systems satisfies a threshold; and in response to determiningthat the change in the number of leases available for the set ofavailable producer systems satisfies the threshold: partitioning thenumber of leases available for individual producer systems among aplurality of leasing agent systems by assigning individual leasing agentsystems from the plurality of leasing agent systems a subset of leasesfrom the number of leases available for individual producer systems; andfor individual leasing agent systems of the plurality of leasing agentsystems, providing the leasing agent system with the subset of leasesassigned to the leasing agent system, whereby the partitioning of thenumber of leases available for individual producer systems among theplurality of leasing agent systems enables a balancing of a workloadamong the plurality of leasing agent systems.
 21. The method of claim20, wherein individual leasing agent systems are assigned anon-overlapping subset of leases.
 22. The method of claim 20, whereinproviding the leasing agent system with the subset of leases excludesproviding the first leasing agent system with the subset of leasesassigned to the leasing agent system.
 23. The method of claim 20,wherein providing the leasing agent system with the subset of leasesassigned to the leasing agent system comprises providing the leasingagent system with the number of leases assigned to the leasing agentsystem for individual producer systems of the plurality of producersystems.
 24. The method of claim 20, wherein providing the leasing agentsystem with the subset of leases assigned to the leasing agent systemcomprises providing the leasing agent system with an identifier forindividual leases assigned to the leasing agent system.
 25. The methodof claim 20, wherein partitioning the number of leases available forindividual producer systems among the plurality of leasing agent systemscomprises partitioning the number of leases available for individualproducer systems substantially equally among the plurality of leasingagent systems.
 26. The method of claim 20, wherein the plurality ofleasing agent systems comprises a subset of a set of leasing agentsystems.
 27. The method of claim 26, wherein the plurality of leasingagent systems includes the first leasing agent system.
 28. The method ofclaim 20, wherein the set of available producer systems comprises asubset of available producer systems.
 29. The method of claim 20,wherein said partitioning the number of leases available for individualproducer systems among the plurality of leasing agent systems occurs inresponse to a number of total leases available among the set ofavailable producer systems at a first time period changing a thresholdamount compared to a second time period.